Sharing the latest protected species peer-reviewed publications from NOAA Fisheries and its partners
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2020 Issue 1
BYCATCH IN GILLNET FISHERIES CONTINUES TO THREATEN CRITICALLY ENDANGERED SMALL CETACEANS The use of synthe c gillnets in commercial and ar sanal fisheries remains the greatest threat to small cetaceans in coastal and riverine habitats, killing hundreds of thousands each year. Brownell et al. (2019) review the status of 13 Cri cally Endangered small cetaceans listed on the IUCN Red List of Threatened Species. The authors stress that due to the dras c decreases in small cetacean popula ons, reducing the risk of entanglement is not enough. The risk must instead be eliminated, especially in small-scale ar sanal fisheries. Alterna ve fishing gear must eventually replace gillnets although few op ons presently exist. Conserva on zones of adequate size with no use of gillnets and strict enforcement must be established to protect Cri cally Endangered small cetaceans. Even with the implementa on of these measures, Brownell et al. (2019) note that there may not be enough me to prevent many of these small cetaceans from going ex nct. They hope to raise awareness of the gillnet bycatch problem for small cetaceans and accelerate development of a solu on. Photo: Vaquita swimming, NOAA Fisheries.
Brownell et al. 2019. Bycatch in gillnet fisheries threatens Cri cally Endangered small cetaceans and other aqua c megafauna. Endangered Species Research 40:285-296. NEW CHALLENGES FOR FISHERIES MANAGEMENT: WHERE RECOVERING PROTECTED SPECIES, INCREASING HABITAT VARIABILITY AND COMMERCIAL FISHERIES MEET New conserva on and management challenges are arising with recovering humpback whale popula ons and increasing environmental variability. In the California Current, the number of humpbacks is increasing as is the number of whale entanglements. To iden fy possible causes of this high entanglement rate, Santora et al. (2020) conducted a retroac ve analysis of oceanographic condi ons, whale entanglement records, and environmental survey data.
From 2014-2016, a marine heat wave (MHW) in the northeast Pacific, dubbed "the warm Blob", contributed to changes in upwelling and in whale prey species' availability and distribu on. As a result of the MHW, humpbacks switched to feeding on prey located in habitats closer to shore and in areas that overlapped with the California Current Dungeness crab fishery. Addi onally, environmental condi ons resul ng from the MHW allowed for a massive bloom of toxic algae resul ng in domoic acid contamina on that delayed the crab season. The combina on of these factors may have led to a greater overlap of fishing gear and humpback whale concentra ons, contribu ng to a 40% increase in whale entanglements. The authors note that climate change and increased variability and intensity of climate events, in combina on with recovering protected species popula ons and important fisheries, are posing new challenges for fisheries management and stress the importance of coopera on, early detec on, and increased communica on.
The authors developed a Habitat Compression Index (HCI), a spa al me series that tracks areas of coastal upwelling and assesses the likelihood of regional ecosystem shi s and shoreward distribu on pa erns of marine top predators; larger values indicate expansion of cool habitat and values below the mean indicate periods when habitat is compressed onshore. The HCI provides an ecosystem toolbox for monitoring and mi ga ng whale entanglement risk and is now being used to develop guidelines for mi ga ng entanglement risk and associated impacts on the crab fishery and is part of the California Current Integrative Ecosystem Assessment. Photo: Humpbacks lunge feeding on northern anchovy in Monterey Bay, CA. Courtesy of D. Calambokidis, Cascadia Research, taken under NMFS Permit.
Santora et al. 2020. Habitat compression and ecosystem shi s as poten al links between marine heatwave and record entanglement. Nature Communications 11, 563. A LOOK AT THE "DEEP REEF REFUGIA HYPOTHESIS": DO DEEPER WATERS PROVIDE REFUGE FOR CORALS DURING HEAT STRESS? Mass coral bleaching primarily occurs when water temperatures reach 1-2oC above normal summer water temperatures for an extended period of me (several weeks) and can lead to extensive coral mortality. With the increased changes in climate, heat stress events have increased in frequency and severity and threaten coral reef ecosystems throughout the world. Some suggest that corals in deeper waters are likely to escape this heat stress due to cooler temperatures at depth. Venegas et al. (2020) used satellite-derived sea surface temperature data along with temporal, spa al, and depth of in situ temperature records to assess the possibility that deep water corals find refuge from bleaching stress because they live in deeper reef habitats. The authors calculated an in situ stress metric using a bleaching threshold bias-adjusted for depth at 457 reef sites among 49 islands in the western and central Pacific Ocean and analyzed 1,453 hea ng events that occurred from 2001-2017. Once they adjusted bleaching thresholds for ‘normal’ condi ons at depth, they found no significant associa on between depth and in-water heat stress, sugges ng that deeper waters generally won’t provide the refuge researchers hypothesized. Further, their study illustrates that combining satellite and in situ temperature data can provide bleaching-relevant heat stress results that allow for a more accurate assessment of shallow reef heat exposure. Photo: NOAA research diver and in situ temperature logger, NOAA Fisheries.
Venegas et al. 2019. The rarity of depth refugia from coral bleaching heat stress in the western and central Pacific Ocean. Scientific Reports 9, 19710.
Other Recent Publications Abundance and Distribution Mar en et al. 2019. Fidelity to natal social groups and ma ng both within and between social groups in an endangered false killer whale (Pseudorca crassidens) popula on. Endangered Species Research
Pu s et al. 2019. Structure and development of Hawaiian deep-water coral communi es on Mauna Loa lava flows. Marine Ecology Progress Series
Wood et al 2019 Rates of increase in gray seal (Halichoerus grypus atlan ca) pupping Wood et al. 2019. Rates of increase in gray seal (Halichoerus grypus atlan ca) pupping at recolonized U.S. sites, 1988-2019. Journal of Mammology Behavior Michel et al. 2019. Limita ons of ac ve removal to manage predatory fish popula ons. North American Journal of Fisheries Management
Pitman et al. 2019. Skin in the game: epidermal molt as a driver of long-distance migra on in whales. Marine Mammal Science Ecology and Climate Change Goldbogen et al. 2019. Why whales are big but not bigger: physiological drivers and ecological limits in the age of ocean giants. Science Heenan et al. 2019. Natural varia on in coral reef trophic structure across environmental gradients. Frontiers in Ecology and the Environment
Notch et al. 2020. Outmigra on survival of wild Chinook salmon smolts through the Sacramento River during historic drought and high water condi ons. Environmental Biology of Fishes
VanWormer et al. 2019. Viral emergence in marine mammals in the North Pacific may be linked to Arc c sea ice reduc on. Scientific Reports Health Banerjee et al. 2019. Baseline health parameters of East Pacific green turtles at Southern California foraging grounds. Chelonian Conservation Biology
Barratclough et al. 2019. Health assessments of common bo lenose dolphins (Tursiops truncatus): past, present, and poten al conserva on applica ons. Frontiers in Veterinary Science
González Barrientos et al. 2019. Saxitoxin poisoning in green turtles (Chelonia mydas) linked to scavenging on mass mortality of Caribbean sharpnose puffer fish (Canthigaster rostrata-Tetraodon dae). Frontiers in Veterinary Science Methods and Technology Avens et al. 2019. Regional comparison of leatherback sea turtle matura on a ributes and reproduc ve longevity. Marine Biology
Harper et al. 2020. Finding Crush: environmental DNA analysis as a tool for tracking the green sea turtle Chelonia mydas in a marine estuary. Frontiers in Marine Science
Norman et al. 2020. Rela onship between per capita births of Cook Inlet belugas and summer salmon runs: age-structured popula on modeling. Ecosphere Taxonomy and Genetics Costa et al. 2019. Ecological divergence and specia on in common bo lenose dolphins in the Western South Atlan c. Journal of Evolutionary Biology
Pearse et al 2019 Sex-dependent dominance maintains migra on supergene in Pearse et al. 2019. Sex dependent dominance maintains migra on supergene in rainbow trout. Nature Ecology and Evolution
About Science Connect This newsle er highlights the latest research on protected species from scien fic publica ons that include one or more NOAA Fisheries authors. It is distributed quarterly with alterna ng issues covering research from U.S. East and West Coast centers and offices. Publica ons can also be accessed via the Protected Species Publications Repository. About the Protected Species Science Branch As part of NOAA Fisheries Office of Science and Technology, we advocate for the use of peer-reviewed science to promote protected species conserva on and recovery. We are dedicated to advancing research and development efforts and fostering coordina on and communica on across NOAA headquarters, regional offices and centers, and other internal and external partners.
Editorial Contacts
Erin McMichael Mridula Srinivasan, Ph.D. Editor Branch Chief (301) 427-8108 (301) 427-8179 [email protected] [email protected]
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