Protected fish spawning aggregations as self-replenishing reservoirs for regional recovery

Dispersal of eggs and larvae from spawning sites is critical to the population dynamics and conservation of marine fishes. For overfished species like critically endangered Nassau grouper (Epinephelus striatus), recovery depends on the fate of eggs spawned at the few remaining aggregation sites. Biophysical models can predict larval dispersal, yet these rely on assumed values of key parameters, such as diffusion and mortality rates, which have historically been difficult or impossible to estimate. We used in situ imaging to record three-dimensional positions of individual eggs and larvae in proximity to oceanographic drifters released into egg plumes from the largest known Nassau grouper spawning aggregation. We then estimated a diffusion–mortality model and applied it to previous years' drifter tracks to evaluate the possibility of retention versus export to nearby sites within 5 days of spawning. Results indicate that larvae were retained locally in 2011 and 2017, with 2011 recruitment being a substantial driver of population recovery on Little Cayman. Export to a nearby island with a depleted population occurred in 2016. After two decades of protection, the population appears to be self-replenishing but also capable of seeding recruitment in the region, supporting calls to incorporate spawning aggregation protections into fisheries management.publishedVersio

Ocean and coastal acidification off New England and Nova Scotia

Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 2 (2015): 182-197, doi:10.5670/oceanog.2015.41.New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the region’s waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acidify the region’s poorly buffered coastal waters. Despite the apparent vulnerability of these waters, and fisheries’ and mariculture’s significant dependence on calcifying species, the community lacks the ability to confidently predict how the region’s ecosystems will respond to continued ocean and coastal acidification. Here, we discuss ocean and coastal acidification processes specific to New England coastal and Nova Scotia shelf waters and review current understanding of the biological consequences most relevant to the region. We also identify key research and monitoring needs to be addressed and highlight existing capacities that should be leveraged to advance a regional understanding of ocean and coastal acidification.This project was supported in part by an appointment to the Internship/Research Participation Program at the Office of Water, US Environmental Protection Agency (EPA), administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Department of Energy and the EPA. JS acknowledges support from NASA grant from NNX14AL84G NASA-CCS

Responses of young-of-the-year bluefish, Pomatomus saltatrix, exposed to contaminants from an urban estuary

Certain populations of young-of-the-year (YOY) bluefish, Pomatomus saltatrix, reside in contaminated estuaries of the mid-Atlantic bight during periods of rapid growth and development. YOY bluefish from the Tuckerton, NJ area of Great Bay (TK) were fed daily in a laboratory with common prey fish, menhaden and mummichog, from two sites: TK (reference) or Hackensack River (HR) (contaminated). Bluefish were also collected from the HR and TK site for analysis. HR-fed and field-caught bluefish and HR prey fish and stomach contents contained significantly elevated concentrations of PCBs, DDTs, and mercury. HR bluefish had reduced growth, feeding, and activity. tPCB and tDDT concentrations in prey in the stomachs of HR bluefish were higher than those in the field-caught specimens. Prey with higher body burdens may become slower and easier to capture. If bluefish are preferentially foraging on such prey, greater amounts of contaminants can be trophically transferred. PCB congeners accumulated at different concentrations creating PCB fingerprints which correlated with feeding ecology of the fish. PCB fingerprints in the HR-fed bluefish were nearly identical to each other and closest to that of the mummichog, their sole prey during the last month of the feeding experiment. PCB fingerprints of field-caught bluefish were similar to menhaden, the dominant prey in HR field bluefish stomachs. In contaminated marine systems PCB fingerprints can be utilized to establish trophic levels and possibly prey preference in individual fish. In addition to altered behavior and growth, the HR-fed and field bluefish had significantly enlarged, irregular thyroid follicles, lined with thickened epithelial cells compared to the TK fish. The mean concentration of dopamine metabolites and the dopaminergic activity levels were significantly lower in HR field fish than in TK field. In contrast the mean concentrations of dopamine and serotonin and their metabolites and norepinephrine were significantly greater in the HR-fed bluefish compared the TK-fed. Overall the exposed fish displayed neurological and hormonal disruptions that may be responsible for their altered behavior and growth. In conclusion, the altered growth, feeding, activity and physiology of YOY bluefish exposed to these contaminated regimes may have detrimental effects on migration fitness and recruitment success.Ph.D.Includes abstractVitaIncludes bibliographical referencesby Allison C. Candelm

Protected fish spawning aggregations as self-replenishing reservoirs for regional recovery.

Dispersal of eggs and larvae from spawning sites is critical to the population dynamics and conservation of marine fishes. For overfished species like critically endangered Nassau grouper (Epinephelus striatus), recovery depends on the fate of eggs spawned at the few remaining aggregation sites. Biophysical models can predict larval dispersal, yet these rely on assumed values of key parameters, such as diffusion and mortality rates, which have historically been difficult or impossible to estimate. We used in situ imaging to record three-dimensional positions of individual eggs and larvae in proximity to oceanographic drifters released into egg plumes from the largest known Nassau grouper spawning aggregation. We then estimated a diffusion-mortality model and applied it to previous years drifter tracks to evaluate the possibility of retention versus export to nearby sites within 5 days of spawning. Results indicate that larvae were retained locally in 2011 and 2017, with 2011 recruitment being a substantial driver of population recovery on Little Cayman. Export to a nearby island with a depleted population occurred in 2016. After two decades of protection, the population appears to be self-replenishing but also capable of seeding recruitment in the region, supporting calls to incorporate spawning aggregation protections into fisheries management

Supplementary methods, figures (S1-S11), and tables (S1-S3) from Protected fish spawning aggregations as self-replenishing reservoirs for regional recovery

Dispersal of eggs and larvae from spawning sites is critical to the population dynamics and conservation of marine fishes. For overfished species like critically endangered Nassau Grouper (Epinephelus striatus), recovery depends on the fate of eggs spawned at the few remaining aggregation sites. Biophysical models can predict larval dispersal, yet these rely on assumed values of key parameters, such as diffusion and mortality rates, which have historically been difficult or impossible to estimate. We used in situ imaging to record three-dimensional positions of individual eggs and larvae in proximity to oceanographic drifters released into egg plumes from the largest known Nassau Grouper spawning aggregation. We then estimated a diffusion-mortality model and applied it to previous years' drifter tracks to evaluate the possibility of retention versus export to nearby sites within five days of spawning. Results indicate that larvae were retained locally in 2011 and 2017, with 2011 recruitment being a substantial driver of population recovery on Little Cayman. Export to a nearby island with a depleted population occurred in 2016. After two decades of protection, the population appears to be self-replenishing but also capable of seeding recruitment in the region, supporting calls to incorporate spawning aggregation protections into fisheries management

Lessons From the Western Atlantic Lionfish Invasion to Inform Management in the Mediterranean

Major invasions of Indo-Pacific lionfish (Pterois volitansandP. miles) areunderway in the Western Atlantic Ocean and the Mediterranean Sea. While the establishment of lionfish in the Western Atlantic is perhaps the most well-studied marine fish invasion to date, the rapidly expanding invasion in the Mediterranean is more recent and has received less attention. Here we review and synthesize successes and failures from two decades of lionfish management in the Western Atlantic to give policy recommendations for their management in the Mediterranean. Two failed approaches that were attempted multiple times in the Western Atlantic and that we advise against are (1) feeding lionfish to native fish to promote predation and (2) implementing bounty programs to incentivize lionfish harvest. Broadly, the most important management lessons that we recommend include (1) conducting routine removals by spearfishing with scuba, which can effectively suppress local abundances of lionfish; (2) encouraging the development of recreational and commercial lionfish fisheries, which can promote long-term, sustainable lionfish population control; and, (3) engaging local communities and resource users (e.g., with lionfish removal tournaments), whichcan concurrently achieve multiple objectives of promoting lionfish removals, market-development, research, and public education. Managers in the Western Atlantic often needed to adapt current conservation policies to enable lionfish removals in areas where spearfishing with scuba was otherwise prohibited for conservation purposes. The risk of abusing these policies was mitigated through the use of gear restrictions, diver trainings, and through participatory approaches that integrated scuba divers and stakeholder organizations in lionfish research and management. Our review of policies and practices in the Mediterranean Sea found that many of our recommended lionfish management approaches are not being done and indicate potential opportunities to implement these. We expect and fully recommend that work continues towards multinational cooperation to facilitate regional coordination of research, control, and management efforts with respect to the Mediterranean lionfish invasion. As with other major biological invasions, lionfish are unconstrained by political borders and their control will require rapid and strategic management approaches with broad cooperation among and between governments and stakeholders