Megan Ladds, Juliette Smith, Vanessa Strohm, Christopher J. Gobler
ABSTRACT: Dinophysis spp. synthesize lipophilic toxins and form harmful algal blooms (HABs) across the globe. Zooplankton can play a role in controlling HABs and be a vector for HAB toxins; however, no study has explored the grazing and survival of copepods fed cultured Dinophysis. Here, the copepod Acartia tonsa isolated from New York, USA, was fed 3 strains of D. acuminata from the eastern USA (Massachutsetts, New York, Virginia), as well as 2 non-toxic prey (Rhodomonas salina and Gymnodinium aureolum). Grazing and survival rates of A. tonsa were quantified along with toxins. A. tonsa fed on D. acuminata at rates similar to R. salina and G. aureolum. Mixed-prey experiments suggested that D. acuminata was not acutely toxic to A. tonsa. Extracellular levels of okadaic acid (OA) significantly increased (p ≤ 0.05) and extracellular pectenotoxin (PTX2) increased by 50% upon exposure to copepods, suggesting that grazers stimulated extracellular toxin release. During 3 wk survival experiments, copepods consuming D. acuminata as a sole food source displayed significantly lower survival rates compared to those fed a control diet of R. salina (p < 0.05). This depressed survivorship was ameliorated by feeding the copepods a diet of D. acuminata mixed with G. aureolum, suggesting that nutritional deficiencies drove mortality. Since grazing on Dinophysis may be low when prey abundance is low, reduced grazing may contribute to bloom development; however, as blooms intensify, grazing may increase, potentially causing a reduction in copepod survival and continued bloom progression. Finally, grazing-induced increases in OA and PTX2 could enhance the introduction of Dinophysis-derived toxins into food webs.
ABSTRACT: Dinophysis spp.会合成亲脂性毒素并在全球范围内形成有害藻华（HABs）。浮游动物可在控制有害藻华方面发挥作用，同时也是有害藻华毒素的传播媒介。在此，研究人员给分离自美国纽约的桡足类 Acartia tonsa 喂食了 3 种来自美国东部（马萨诸塞州、纽约州和弗吉尼亚州）的 D. acuminata 菌株以及 2 种无毒猎物（Rhodomonas salina 和 Gymnodinium aureolum）。对扁囊藻的捕食率和存活率以及毒素进行了量化。A. tonsa捕食 D. acuminata 的比率与 R. salina 和 G. aureolum 相似。混合捕食实验表明，D. acuminata 对扁豆虫没有急性毒性。暴露于桡足类后，细胞外 okadaic 酸（OA）水平显著增加（p ≤ 0.05），细胞外 pectenotoxin（PTX2）增加了 50%，表明食草动物刺激了细胞外毒素的释放。在为期 3 周的存活实验中，与饲喂盐渍桡足类对照食物的桡足类相比，仅以 D. acuminata 为食物来源的桡足类存活率明显较低（p < 0.05）。给桡足类喂食混有金线莲的 D. acuminata 后，存活率下降的情况有所改善，这表明营养缺乏导致了死亡。由于在猎物丰度较低时，对Dinophysis的捕食可能较少，因此减少捕食可能有助于藻华的发展；然而，随着藻华的加剧，捕食可能会增加，从而可能导致桡足类存活率下降和藻华继续发展。最后，放牧引起的 OA 和 PTX2 的增加可能会促进 Dinophysis 衍生毒素进入食物网。
{"title":"Acartia tonsa grazing on the harmful dinoflagellate Dinophysis acuminata reduces copepod survival and increases extracellular toxin concentrations","authors":"Megan Ladds, Juliette Smith, Vanessa Strohm, Christopher J. Gobler","doi":"10.3354/meps14666","DOIUrl":"https://doi.org/10.3354/meps14666","url":null,"abstract":"ABSTRACT: <i>Dinophysis</i> spp. synthesize lipophilic toxins and form harmful algal blooms (HABs) across the globe. Zooplankton can play a role in controlling HABs and be a vector for HAB toxins; however, no study has explored the grazing and survival of copepods fed cultured <i>Dinophysis</i>. Here, the copepod <i>Acartia tonsa</i> isolated from New York, USA, was fed 3 strains of <i>D. acuminata</i> from the eastern USA (Massachutsetts, New York, Virginia), as well as 2 non-toxic prey (<i>Rhodomonas salina</i> and <i>Gymnodinium aureolum</i>). Grazing and survival rates of <i>A. tonsa</i> were quantified along with toxins. <i>A. tonsa</i> fed on <i>D. acuminata</i> at rates similar to <i>R. salina</i> and <i>G. aureolum.</i> Mixed-prey experiments suggested that <i>D. acuminata</i> was not acutely toxic to <i>A. tonsa.</i> Extracellular levels of okadaic acid (OA) significantly increased (p ≤ 0.05) and extracellular pectenotoxin (PTX2) increased by 50% upon exposure to copepods, suggesting that grazers stimulated extracellular toxin release. During 3 wk survival experiments, copepods consuming <i>D. acuminata</i> as a sole food source displayed significantly lower survival rates compared to those fed a control diet of <i>R. salina</i> (p < 0.05). This depressed survivorship was ameliorated by feeding the copepods a diet of <i>D. acuminata</i> mixed with <i>G. aureolum</i>, suggesting that nutritional deficiencies drove mortality. Since grazing on <i>Dinophysis</i> may be low when prey abundance is low, reduced grazing may contribute to bloom development; however, as blooms intensify, grazing may increase, potentially causing a reduction in copepod survival and continued bloom progression. Finally, grazing-induced increases in OA and PTX2 could enhance the introduction of <i>Dinophysis</i>-derived toxins into food webs.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"117 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joseph M. Smith, Brian J. Burke, Doug Jackson, Brian Wells, Brian Beckman, Will Duguid, Thomas P. Quinn, David D. Huff
ABSTRACT: The present study quantified the vertical and horizontal distribution of sub-adult Chinook salmon Oncorhynchus tshawytscha in nearshore marine environments. Depth-specific hook and line sampling was conducted along the Pacific Ocean coast of Washington, USA. Our analysis, based on 187 Chinook salmon from 1299 sampling deployments and 6616 hooks, revealed a wide distribution of salmon in nearshore marine waters, with distinct patterns associated with fish size and age. Chinook salmon that spent one winter in marine waters were more likely to be caught at greater depths than those in their first year at sea, and larger fish were found at greater depths than smaller fish. The probability of Chinook salmon capture varied with depth, showing a higher likelihood of capture at midwater (>15 m from the surface and >5 m from the bottom) and near (<5 m) the bottom compared to near (<15 m) the surface. Additionally, environmental variables such as sea surface temperature, sea surface chlorophyll a, minutes to low tide, and boat speed unimodally influenced capture probability. Our study contributes valuable insights into the spatiotemporal ecology of Chinook salmon, offering a more mechanistic perspective for their management and conservation. The identified relationships between environmental covariates and Chinook salmon distribution can be used to inform life cycle models used to manage and protect this at-risk species and the ecosystem processes that depend on them, particularly in the context of changing oceanic conditions and their role as both predator and prey in marine ecosystems.
{"title":"Marine biophysical conditions influence the vertical and horizontal distribution of sub-adult Chinook salmon in nearshore marine waters","authors":"Joseph M. Smith, Brian J. Burke, Doug Jackson, Brian Wells, Brian Beckman, Will Duguid, Thomas P. Quinn, David D. Huff","doi":"10.3354/meps14672","DOIUrl":"https://doi.org/10.3354/meps14672","url":null,"abstract":"ABSTRACT: The present study quantified the vertical and horizontal distribution of sub-adult Chinook salmon <i>Oncorhynchus tshawytscha</i> in nearshore marine environments. Depth-specific hook and line sampling was conducted along the Pacific Ocean coast of Washington, USA. Our analysis, based on 187 Chinook salmon from 1299 sampling deployments and 6616 hooks, revealed a wide distribution of salmon in nearshore marine waters, with distinct patterns associated with fish size and age. Chinook salmon that spent one winter in marine waters were more likely to be caught at greater depths than those in their first year at sea, and larger fish were found at greater depths than smaller fish. The probability of Chinook salmon capture varied with depth, showing a higher likelihood of capture at midwater (>15 m from the surface and >5 m from the bottom) and near (<5 m) the bottom compared to near (<15 m) the surface. Additionally, environmental variables such as sea surface temperature, sea surface chlorophyll <i>a</i>, minutes to low tide, and boat speed unimodally influenced capture probability. Our study contributes valuable insights into the spatiotemporal ecology of Chinook salmon, offering a more mechanistic perspective for their management and conservation. The identified relationships between environmental covariates and Chinook salmon distribution can be used to inform life cycle models used to manage and protect this at-risk species and the ecosystem processes that depend on them, particularly in the context of changing oceanic conditions and their role as both predator and prey in marine ecosystems.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"26 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. R. Sisti, B. Jellison, J. D. Shields, E. B. Rivest
ABSTRACT: The relationship between adverse environmental conditions and grooming behavior is an unresolved mechanism whereby a changing climate may impact reproductive success in animals that brood their eggs. Although important to embryo survival and development in decapod crustaceans, brood grooming by ovigerous females may be impacted by energetically demanding conditions associated with climate change, which may contribute to lethal and sublethal outcomes for brood health and survival. Despite its potential importance to reproduction, brood-grooming behavior has not been empirically described in the American lobster Homarus americanus H. Milne Edwards, 1837, a commercially important marine decapod. The relationship between brood-grooming behavior, temperature, and pH was explored at different points in the embryogenesis of American lobsters. For a period of 5 mo, egg-bearing females were exposed to different combinations of ecologically relevant conditions of temperature and pH, including those reflecting ocean warming (+4°C), ocean acidification (-0.5 pH), and the combination of warming and acidification. Fecundity, embryo development, and female grooming behavior were assessed at multiple time points. The proportion of time that lobsters spent fanning, but not probing, their broods increased with advancing embryo development. Neither egg loss, nor any measured brood-grooming behaviors, varied significantly with temperature or pH in this experiment. American lobster reproduction appears well suited to tolerate future conditions of ocean acidification and warming based on the ability to maintain stable brood grooming and brood mortality levels under a range of conditions.
摘要：不利的环境条件与理毛行为之间的关系是一个尚未解决的机制，气候变化可能会影响产卵动物的繁殖成功率。尽管对十足甲壳类动物胚胎的存活和发育很重要，但有卵雌性动物的育雏梳理行为可能会受到与气候变化相关的高能耗条件的影响，这可能会对雏鸟的健康和存活造成致命或亚致命的结果。尽管梳理育雏行为对繁殖具有潜在的重要性，但对于具有重要商业价值的海洋十足目动物--美国龙虾（Homarus americanus H. Milne Edwards, 1837）来说，梳理育雏行为尚未得到实证描述。我们在美洲龙虾胚胎发育的不同阶段探讨了梳理行为、温度和 pH 值之间的关系。在为期5个月的时间里，产卵雌性龙虾暴露在不同的生态相关温度和pH值条件组合中，包括反映海洋变暖（+4°C）、海洋酸化（-0.5 pH）以及变暖和酸化组合的条件。在多个时间点对龙虾的繁殖力、胚胎发育和雌性梳理行为进行了评估。随着胚胎发育的推进，龙虾用于扇动而非探测雏鸟的时间比例增加。在该实验中，卵的损失和任何测量的育雏行为都不会随温度或 pH 值的变化而显著改变。美国龙虾的繁殖似乎非常适合承受未来海洋酸化和变暖的条件，因为它能够在各种条件下保持稳定的雏鸟梳理和雏鸟死亡率水平。
{"title":"Brood-grooming behavior of American lobsters Homarus americanus in conditions of ocean warming and acidification","authors":"A. R. Sisti, B. Jellison, J. D. Shields, E. B. Rivest","doi":"10.3354/meps14667","DOIUrl":"https://doi.org/10.3354/meps14667","url":null,"abstract":"ABSTRACT: The relationship between adverse environmental conditions and grooming behavior is an unresolved mechanism whereby a changing climate may impact reproductive success in animals that brood their eggs. Although important to embryo survival and development in decapod crustaceans, brood grooming by ovigerous females may be impacted by energetically demanding conditions associated with climate change, which may contribute to lethal and sublethal outcomes for brood health and survival. Despite its potential importance to reproduction, brood-grooming behavior has not been empirically described in the American lobster <i>Homarus americanus</i> H. Milne Edwards, 1837, a commercially important marine decapod. The relationship between brood-grooming behavior, temperature, and pH was explored at different points in the embryogenesis of American lobsters. For a period of 5 mo, egg-bearing females were exposed to different combinations of ecologically relevant conditions of temperature and pH, including those reflecting ocean warming (+4°C), ocean acidification (-0.5 pH), and the combination of warming and acidification. Fecundity, embryo development, and female grooming behavior were assessed at multiple time points. The proportion of time that lobsters spent fanning, but not probing, their broods increased with advancing embryo development. Neither egg loss, nor any measured brood-grooming behaviors, varied significantly with temperature or pH in this experiment. American lobster reproduction appears well suited to tolerate future conditions of ocean acidification and warming based on the ability to maintain stable brood grooming and brood mortality levels under a range of conditions.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"40 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: Epibiosis is shaped by a complex interplay of biotic interactions involving hosts, epibionts, and mobile consumers. In temperate waters, consumer control by mesograzers prevents complete overgrowth of seaweeds. In polar waters, the mechanisms determining the abundances of sessile organisms associated with seaweeds are unknown. We empirically assessed the strength of the consumer control effect on the colonization of the sub-arctic red seaweed Phycodrys rubens by caging individual plants in the field in the shallow subtidal of the White Sea (65°N). We compared epibiosis on plants in consumer exclosure cages, in cages with the mesopredatory shrimp Spirontocaris phippsii, in semi-enclosed cages, and on unmanipulated plants in a cold year (2014) and a warm year (2015). Despite the dramatic interannual variation in consumer control, the mean total cover of epibionts in the absence of consumers never exceeded 15%. While consumers had a substantial effect on the total epibiont cover in the warm year and a nearly negligible effect in the cold year, the total cover of unmanipulated algae was similar in 2014 and 2015. Bryozoans, which were selectively impacted by consumers—particularly shrimp—dominated in both years. However, bryozoan abundance was much lower in 2015, when the abundance of hydroids, sponges, and bivalves—less affected by consumers—increased. Consumer control is not a key factor preventing most Phycodrys plants from being heavily overgrown. Yet, smaller plants, which have a higher epibiont cover, may indirectly benefit from consumers. Future climate changes are likely to make the Phycodrys epibiosis increasingly top-down regulated.
{"title":"Variation in top-down control of red algae epibiosis in the White Sea","authors":"Alexandra Chava, Anna Artemieva, Eugeniy Yakovis","doi":"10.3354/meps14664","DOIUrl":"https://doi.org/10.3354/meps14664","url":null,"abstract":"ABSTRACT: Epibiosis is shaped by a complex interplay of biotic interactions involving hosts, epibionts, and mobile consumers. In temperate waters, consumer control by mesograzers prevents complete overgrowth of seaweeds. In polar waters, the mechanisms determining the abundances of sessile organisms associated with seaweeds are unknown. We empirically assessed the strength of the consumer control effect on the colonization of the sub-arctic red seaweed <i>Phycodrys rubens</i> by caging individual plants in the field in the shallow subtidal of the White Sea (65°N). We compared epibiosis on plants in consumer exclosure cages, in cages with the mesopredatory shrimp <i>Spirontocaris phippsii</i>, in semi-enclosed cages, and on unmanipulated plants in a cold year (2014) and a warm year (2015). Despite the dramatic interannual variation in consumer control, the mean total cover of epibionts in the absence of consumers never exceeded 15%. While consumers had a substantial effect on the total epibiont cover in the warm year and a nearly negligible effect in the cold year, the total cover of unmanipulated algae was similar in 2014 and 2015. Bryozoans, which were selectively impacted by consumers—particularly shrimp—dominated in both years. However, bryozoan abundance was much lower in 2015, when the abundance of hydroids, sponges, and bivalves—less affected by consumers—increased. Consumer control is not a key factor preventing most <i>Phycodrys</i> plants from being heavily overgrown. Yet, smaller plants, which have a higher epibiont cover, may indirectly benefit from consumers. Future climate changes are likely to make the <i>Phycodrys</i> epibiosis increasingly top-down regulated.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"38 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ashley M. Blawas, Lauren E. Miller, Jeanne M. Shearer, William R. Cioffi, Daniel L. Webster, Zachary T. Swaim, Heather J. Foley, Danielle M. Waples, Nicola J. Quick, Douglas P. Nowacek, Andrew J. Read
ABSTRACT: Aerobic dive limits (ADLs) are a useful paradigm for assessing marine mammal diving ability. Given the allometry of total body oxygen stores and metabolic rate, larger animals should have increased diving capacities and thus elevated ADLs. The short-finned pilot whale Globicephala macrorhynchus is a deep-diving species with pronounced sexual size dimorphism, and individuals are regularly found in size-mixed groups. Therefore, we asked how body size constrains dive durations in this species and whether behavioral ADL (bADL), estimated as the 95th percentile of dive duration, is a useful measure of physiological ADL. We analyzed 30169 dives from 45 animals tagged with satellite-linked recorders off Cape Hatteras, North Carolina, and Jacksonville, Florida, USA, and determined a species-level bADL of 18.8 min and individual bADLs ranging from 13.9 to 22.1 min. To assess the influence of size on bADL, we estimated the body lengths of 19 whales from dorsal fin measurements. Body length did not fully explain intraspecific bADL variation, but similar dive distributions and lower bADL variance between animals tagged together indicated a potential effect of group membership. Moreover, individuals in Cape Hatteras had a significantly lower median bADL than those in Jacksonville, suggesting location may influence dive durations. These results indicate the potential impact of social and location-specific factors on bADL estimates in a deep-diving, sexually dimorphic species.
{"title":"Aerobic dive limit in short-finned pilot whales Globicephala macrorhynchus: an assessment of behavioral criteria","authors":"Ashley M. Blawas, Lauren E. Miller, Jeanne M. Shearer, William R. Cioffi, Daniel L. Webster, Zachary T. Swaim, Heather J. Foley, Danielle M. Waples, Nicola J. Quick, Douglas P. Nowacek, Andrew J. Read","doi":"10.3354/meps14670","DOIUrl":"https://doi.org/10.3354/meps14670","url":null,"abstract":"ABSTRACT: Aerobic dive limits (ADLs) are a useful paradigm for assessing marine mammal diving ability. Given the allometry of total body oxygen stores and metabolic rate, larger animals should have increased diving capacities and thus elevated ADLs. The short-finned pilot whale <i>Globicephala macrorhynchus</i> is a deep-diving species with pronounced sexual size dimorphism, and individuals are regularly found in size-mixed groups. Therefore, we asked how body size constrains dive durations in this species and whether behavioral ADL (bADL), estimated as the 95th percentile of dive duration, is a useful measure of physiological ADL. We analyzed 30169 dives from 45 animals tagged with satellite-linked recorders off Cape Hatteras, North Carolina, and Jacksonville, Florida, USA, and determined a species-level bADL of 18.8 min and individual bADLs ranging from 13.9 to 22.1 min. To assess the influence of size on bADL, we estimated the body lengths of 19 whales from dorsal fin measurements. Body length did not fully explain intraspecific bADL variation, but similar dive distributions and lower bADL variance between animals tagged together indicated a potential effect of group membership. Moreover, individuals in Cape Hatteras had a significantly lower median bADL than those in Jacksonville, suggesting location may influence dive durations. These results indicate the potential impact of social and location-specific factors on bADL estimates in a deep-diving, sexually dimorphic species.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"60 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Douglas J. McCauley, John K. Parsons, Charles A. Braman, James M. Anderson, Jennifer E. Caselle, Emma J. Critchley, Aidan Glina, Francis H. Joyce, Christopher G. Lowe, Samantha Mladjov, Neil Nathan, Patrick T. Rex, Emily Spurgeon, Brian S. Stirling, Hillary S. Young
ABSTRACT: Ontogenetic habitat shifts are a common feature of many marine species, including sharks, which face conservation threats when their distributions overlap with human resource extraction and habitat modification. White sharks Carcharodon carcharias, for example, exhibit a distinctly coastal phase as juveniles, with a limited distribution compared to the basin-scale range of adults. Using an unoccupied aerial vehicle (UAV), we studied a coastal aggregation site within a Southern California Bight nursery area to determine how fine-scale temporal and oceanographic factors affect white sharks at different developmental stages. White shark density, as measured via UAV, was highly variable across time of day and day of year, with modest variation across years. Typically, more sharks were observed in the late afternoon hours. Sharks, especially those <3 m total length, were observed more often during periods of colder seafloor temperatures, potentially reflecting avoidance of these colder, deeper waters by more cold-intolerant smaller white sharks. Alternate models incorporating sea surface temperature showed a very small but significant association between surface temperatures and <3 m total length white sharks for the months we surveyed, but no such association for larger sharks. There were no or only modest effects of visibility, swell height, chl a levels, sea state, and tidal height on UAV-observed shark density. Understanding how temporal patterns and oceanographic predictors of density change over time as well as how shark ontogeny interacts with these factors can help us to better understand how this species uses coastal habitats and predict when they may be more likely to share marine space with humans.
{"title":"Temporal and oceanographic factors differentially affect two size classes of white shark at a Southern California aggregation site","authors":"Douglas J. McCauley, John K. Parsons, Charles A. Braman, James M. Anderson, Jennifer E. Caselle, Emma J. Critchley, Aidan Glina, Francis H. Joyce, Christopher G. Lowe, Samantha Mladjov, Neil Nathan, Patrick T. Rex, Emily Spurgeon, Brian S. Stirling, Hillary S. Young","doi":"10.3354/meps14680","DOIUrl":"https://doi.org/10.3354/meps14680","url":null,"abstract":"ABSTRACT: Ontogenetic habitat shifts are a common feature of many marine species, including sharks, which face conservation threats when their distributions overlap with human resource extraction and habitat modification. White sharks <i>Carcharodon carcharias</i>, for example, exhibit a distinctly coastal phase as juveniles, with a limited distribution compared to the basin-scale range of adults. Using an unoccupied aerial vehicle (UAV), we studied a coastal aggregation site within a Southern California Bight nursery area to determine how fine-scale temporal and oceanographic factors affect white sharks at different developmental stages. White shark density, as measured via UAV, was highly variable across time of day and day of year, with modest variation across years. Typically, more sharks were observed in the late afternoon hours. Sharks, especially those <3 m total length, were observed more often during periods of colder seafloor temperatures, potentially reflecting avoidance of these colder, deeper waters by more cold-intolerant smaller white sharks. Alternate models incorporating sea surface temperature showed a very small but significant association between surface temperatures and <3 m total length white sharks for the months we surveyed, but no such association for larger sharks. There were no or only modest effects of visibility, swell height, chl <i>a</i> levels, sea state, and tidal height on UAV-observed shark density. Understanding how temporal patterns and oceanographic predictors of density change over time as well as how shark ontogeny interacts with these factors can help us to better understand how this species uses coastal habitats and predict when they may be more likely to share marine space with humans.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"38 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jacob Burbank, Brianne Kelly, Alex Hanke, Hugues P. Benoît, Michael Power
ABSTRACT: Upper trophic level predators can greatly influence the dynamics and productivity of forage fish species. Quantifying this influence requires information on prey consumption; however, establishing feeding habits of highly mobile predators is particularly challenging. Stable isotopes of carbon and nitrogen (δ13C and δ15N) have been applied to characterize the trophic ecology of Atlantic bluefin tuna Thunnusthynnus (ABFT) in several important regions; however, applications in Canada are lacking. Here, we used δ13C and δ15N values of ABFT muscle tissue collected in 2014-2018 on 2 important foraging grounds along the coast of Atlantic Canada to evaluate the temporally integrated trophic ecology of this ecologically and commercially important species. Populations of some small pelagic fish species in these areas have been depleted, and predation by ABFT is considered a potentially important contributor. Isotopic diet reconstructions found that Atlantic mackerel were the dominant prey in the southern Gulf of St. Lawrence, and a combination of Atlantic herring and sandlance were the most dominant prey consumed on the Scotian Shelf. Diet reconstructions identified an ontogenetic shift in prey consumption, with more sandlance consumed by smaller ABFT and a shift to higher consumption of Atlantic mackerel and Atlantic herring as fish increased in size. Isotopic niche overlap indicated relatively high overlap for adults among years, suggesting that ABFT did not show substantial inter-annual variation in their trophic ecology. Overall, the study provides insight into the trophic ecology of ABFT along the Atlantic Coast of Canada that can be integrated into investigations of predator impacts on depleted mackerel and herring populations.
{"title":"Ontogenetic shifts in isotope-inferred trophic ecology of Atlantic bluefin tuna Thunnus thynnus in Atlantic Canada","authors":"Jacob Burbank, Brianne Kelly, Alex Hanke, Hugues P. Benoît, Michael Power","doi":"10.3354/meps14669","DOIUrl":"https://doi.org/10.3354/meps14669","url":null,"abstract":"ABSTRACT: Upper trophic level predators can greatly influence the dynamics and productivity of forage fish species. Quantifying this influence requires information on prey consumption; however, establishing feeding habits of highly mobile predators is particularly challenging. Stable isotopes of carbon and nitrogen (δ<sup>13</sup>C and δ<sup>15</sup>N) have been applied to characterize the trophic ecology of Atlantic bluefin tuna <i>Thunnus</i> <i>thynnus</i> (ABFT) in several important regions; however, applications in Canada are lacking. Here, we used δ<sup>13</sup>C and δ<sup>15</sup>N values of ABFT muscle tissue collected in 2014-2018 on 2 important foraging grounds along the coast of Atlantic Canada to evaluate the temporally integrated trophic ecology of this ecologically and commercially important species. Populations of some small pelagic fish species in these areas have been depleted, and predation by ABFT is considered a potentially important contributor. Isotopic diet reconstructions found that Atlantic mackerel were the dominant prey in the southern Gulf of St. Lawrence, and a combination of Atlantic herring and sandlance were the most dominant prey consumed on the Scotian Shelf. Diet reconstructions identified an ontogenetic shift in prey consumption, with more sandlance consumed by smaller ABFT and a shift to higher consumption of Atlantic mackerel and Atlantic herring as fish increased in size. Isotopic niche overlap indicated relatively high overlap for adults among years, suggesting that ABFT did not show substantial inter-annual variation in their trophic ecology. Overall, the study provides insight into the trophic ecology of ABFT along the Atlantic Coast of Canada that can be integrated into investigations of predator impacts on depleted mackerel and herring populations.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"86 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ileana F. Fenwick, Kurt C. Heim, Andrew J. Pershing, Kathy E. Mills, Sean M. Lucey, Janet A. Nye
ABSTRACT: As climate change intensifies, there is a pressing concern regarding how ecological communities respond to disturbances occurring at different intensities and time scales. We explored how the type of disturbance influences the dynamics of a marine community. A pulse disturbance is an abrupt, high-magnitude shift in conditions that can cause immediate and significant impacts to an ecological community. Alternatively, press disturbances are long-term, multi-generational pressures acting on communities over time. The Northeast US Continental Shelf Large Marine Ecosystem (NES LME) is one of the fastest-warming regions in the world and has experienced historic overfishing. Assemblage shifts in the NES LME have previously been characterized; however, these were prior to an unprecedented pulse disturbance marine heatwave (MHW) event in 2012 followed by punctuated MHWs over the last decade. We quantified community change across the NES LME using a community trajectory analysis, a multivariate tool that utilizes geometric analyses and comparisons of community trajectories, to quantify shifts in dynamic beta diversity. We hypothesized that the pulse MHWs would strongly influence ecosystem structure; however, no significant impact was detected. Our analysis indicates that the NES LME continues to tropicalize. However, it was not the pulse MHW events that seemed to drive change but rather ecosystem overfishing and rising temperatures. We quantified beta diversity over time in marine communities undergoing abrupt environmental changes and press disturbances. When expanded globally, this analysis can compare how variable disturbance pressures may result in different manifestations of beta diversity change within marine assemblages.
{"title":"Evaluating the influence of press and pulse disturbances on community dynamics of the Northeast US Large Marine Ecosystem","authors":"Ileana F. Fenwick, Kurt C. Heim, Andrew J. Pershing, Kathy E. Mills, Sean M. Lucey, Janet A. Nye","doi":"10.3354/meps14663","DOIUrl":"https://doi.org/10.3354/meps14663","url":null,"abstract":"ABSTRACT: As climate change intensifies, there is a pressing concern regarding how ecological communities respond to disturbances occurring at different intensities and time scales. We explored how the type of disturbance influences the dynamics of a marine community. A pulse disturbance is an abrupt, high-magnitude shift in conditions that can cause immediate and significant impacts to an ecological community. Alternatively, press disturbances are long-term, multi-generational pressures acting on communities over time. The Northeast US Continental Shelf Large Marine Ecosystem (NES LME) is one of the fastest-warming regions in the world and has experienced historic overfishing. Assemblage shifts in the NES LME have previously been characterized; however, these were prior to an unprecedented pulse disturbance marine heatwave (MHW) event in 2012 followed by punctuated MHWs over the last decade. We quantified community change across the NES LME using a community trajectory analysis, a multivariate tool that utilizes geometric analyses and comparisons of community trajectories, to quantify shifts in dynamic beta diversity. We hypothesized that the pulse MHWs would strongly influence ecosystem structure; however, no significant impact was detected. Our analysis indicates that the NES LME continues to tropicalize. However, it was not the pulse MHW events that seemed to drive change but rather ecosystem overfishing and rising temperatures. We quantified beta diversity over time in marine communities undergoing abrupt environmental changes and press disturbances. When expanded globally, this analysis can compare how variable disturbance pressures may result in different manifestations of beta diversity change within marine assemblages.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"64 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Angela R. Korabik, Suellen M. Dias, Genece V. Grisby, Edwin D. Grosholz
ABSTRACT: Estuarine habitats regularly experience large variations in abiotic conditions such as temperature and salinity; however, under climate change and the increasing threat of invasive species, the pressure from both abiotic and biotic stresses has been increasing. Several studies have investigated the interactions of the adult stages of macroalgae; however, there is little understanding of how microscopic stages of Macrocystis pyrifera and Sargassum muticum interact or how climate change may influence this interaction. Our research considers the effects of climate-driven changes in temperature and salinity and their interactions with S. muticum on the growth and survival of M. pyrifera gametophytes from Tomales Bay, CA, USA. Using kelp culturing experiments, we tested (1) how different salinities and temperatures impact early life stages M. pyrifera from different sources within Tomales Bay, (2) how the presence of invasive S. muticum propagules affect M. pyrifera gametophyte development, and (3) how the combined effects of salinity, temperature, and S. muticum presence affect M. pyrifera early life stages. Our results suggest that M. pyrifera may be able to adapt to local conditions like salinity; however, higher temperatures from a changing climate and the presence of competitors from biological invasions act additively, but not interactively, to negatively impact the early life stages of kelp. By determining how foundation species respond to various abiotic and biotic stressors, we can better predict how these species will perform in a changing environment and how they will contribute to overall ecosystem resilience.
摘要：河口生境经常会经历非生物条件（如温度和盐度）的巨大变化；然而，在气候变化和入侵物种威胁不断增加的情况下，来自非生物和生物压力的压力也在不断增加。有几项研究调查了大型藻类成体阶段的相互作用；然而，人们对巨尾藻和马尾藻的微观阶段如何相互作用以及气候变化可能如何影响这种相互作用知之甚少。我们的研究考虑了气候驱动的温度和盐度变化及其与 S. muticum 的相互作用对美国加利福尼亚州托马雷斯湾马尾藻配子体的生长和存活的影响。通过海带培养实验，我们测试了（1）不同的盐度和温度如何影响托马莱斯湾不同来源的海带，（2）入侵的S. muticum繁殖体如何影响海带配子体的发育，以及（3）盐度、温度和S. muticum的综合影响如何影响海带的早期生命阶段。我们的研究结果表明，海带可能能够适应当地的盐度等条件；但是，气候变化导致的温度升高以及生物入侵带来的竞争者的存在，会对海带的早期生命阶段产生负面影响，而不是相互影响。通过确定基础物种如何应对各种非生物和生物压力因素，我们可以更好地预测这些物种在不断变化的环境中的表现，以及它们将如何促进整个生态系统的恢复能力。
{"title":"Increased temperatures impact the reproduction of localized estuarine kelp populations more than salinity or invasive species","authors":"Angela R. Korabik, Suellen M. Dias, Genece V. Grisby, Edwin D. Grosholz","doi":"10.3354/meps14659","DOIUrl":"https://doi.org/10.3354/meps14659","url":null,"abstract":"ABSTRACT: Estuarine habitats regularly experience large variations in abiotic conditions such as temperature and salinity; however, under climate change and the increasing threat of invasive species, the pressure from both abiotic and biotic stresses has been increasing. Several studies have investigated the interactions of the adult stages of macroalgae; however, there is little understanding of how microscopic stages of <i>Macrocystis pyrifera</i> and <i>Sargassum muticum</i> interact or how climate change may influence this interaction. Our research considers the effects of climate-driven changes in temperature and salinity and their interactions with <i>S. muticum</i> on the growth and survival of <i>M. pyrifera</i> gametophytes from Tomales Bay, CA, USA. Using kelp culturing experiments, we tested (1) how different salinities and temperatures impact early life stages <i>M. pyrifera</i> from different sources within Tomales Bay, (2) how the presence of invasive <i>S. muticum</i> propagules affect <i>M. pyrifera</i> gametophyte development, and (3) how the combined effects of salinity, temperature, and <i>S. muticum</i> presence affect <i>M. pyrifera</i> early life stages. Our results suggest that <i>M. pyrifera</i> may be able to adapt to local conditions like salinity; however, higher temperatures from a changing climate and the presence of competitors from biological invasions act additively, but not interactively, to negatively impact the early life stages of kelp. By determining how foundation species respond to various abiotic and biotic stressors, we can better predict how these species will perform in a changing environment and how they will contribute to overall ecosystem resilience.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"101 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: Despite the consensus that the distribution of functional traits within a community provides insights into community assembly and maintenance mechanisms, few studies have explored spatio-seasonal variations in the functional patterns of marine fish communities. Seven functional traits within the context of 2 distinct groups—habitat use and trophic niche—were selected to assess functional richness (FRic), functional evenness (FEve), and functional dispersion (FDis) across various spatio-seasonal scales. Community-weighted mean redundancy analysis (CWM-RDA) was used to identify the impact of environmental factors on dominant traits. We found seasonal and spatial variations in dominant traits of the fish community, notably influenced by the latitudinal-depth gradient (from shallower stations in the north to deeper stations in the south), east-west (longitudinal) dynamics, and temperature gradient. Latitude was negatively correlated with the CWM values of most functional trait categories. FRic showed more pronounced seasonal variations than other indices, with higher values observed in autumn. Fish assemblages displayed more similarity in functional traits in winter than in other seasons, with lower FRic, higher FEve, and lower FDis. Overall, our findings illustrate that fish assemblages undergo continuous formation and dissolution across different seasons and zones, resulting in various forms of functional diversity patterns.
{"title":"Spatio-seasonal variations in functional trait composition and diversity patterns of marine fish communities in coastal waters","authors":"Jiao Wang, Binduo Xu, Chongliang Zhang, Yupeng Ji, Ying Xue, Yiping Ren","doi":"10.3354/meps14671","DOIUrl":"https://doi.org/10.3354/meps14671","url":null,"abstract":"ABSTRACT: Despite the consensus that the distribution of functional traits within a community provides insights into community assembly and maintenance mechanisms, few studies have explored spatio-seasonal variations in the functional patterns of marine fish communities. Seven functional traits within the context of 2 distinct groups—habitat use and trophic niche—were selected to assess functional richness (FRic), functional evenness (FEve), and functional dispersion (FDis) across various spatio-seasonal scales. Community-weighted mean redundancy analysis (CWM-RDA) was used to identify the impact of environmental factors on dominant traits. We found seasonal and spatial variations in dominant traits of the fish community, notably influenced by the latitudinal-depth gradient (from shallower stations in the north to deeper stations in the south), east-west (longitudinal) dynamics, and temperature gradient. Latitude was negatively correlated with the CWM values of most functional trait categories. FRic showed more pronounced seasonal variations than other indices, with higher values observed in autumn. Fish assemblages displayed more similarity in functional traits in winter than in other seasons, with lower FRic, higher FEve, and lower FDis. Overall, our findings illustrate that fish assemblages undergo continuous formation and dissolution across different seasons and zones, resulting in various forms of functional diversity patterns.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"397 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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