Chapter 5 A COMPARATIVE REVIEW OF MACROMEDUSAE IN EASTERN BOUNDARY CURRENTS

oceanography, climate change, reefs, marine science, marine conservation, marine researc

A Comparative Review of Macromedusae in Eastern Boundary Currents

Edited By: S. J. Hawkins, A. J. Lemasson, A. L. Allcock, A. E. Bates, M. Byrne, A. J. Evans, L. B. Firth, E. M. Marzinelli, B. D. Russell, I. P. Smith, S. E. Swearer, P. A. Todd.The productive eastern boundary current (EBC) systems provide significant sources of global marine protein and have been subject to intense research over the last 50 years. Yet large jellyfish, which are present in all four major systems, have seldom been included in otherwise comprehensive reviews. This undoubtedly reflects their lack of intrinsic commercial value, and the consequently slow pace of knowledge generation. We attempt to redress that imbalance here and to consolidate disparate information on the macromedusae of EBC systems. With the exception of the Canary Current system, which supports a generally low biomass of mostly subtropical taxa, 372jellyfish assemblages in the Benguela, Humboldt and California Current systems are dominated by cool water taxa that can occur at high abundances. While there are large gaps in knowledge, which are highlighted, it is clear that jellyfish can play significant ecological roles in each system. Although there may be strong similarities in faunal composition among the different systems, there are pronounced differences in population responses to the environment and in system resilience and these are reviewed and discussed.Variously, we would also like to thank the Namibian government for access to data and to the National Research Foundation (South Africa), the Royal Society (London), the EAF Nansen Programme and the University of the Western Cape for financial support over the years. We are grateful to the Chilean government and the Agencia Nacional de Investigación y Desarrollo de Chile – formerly Comisión Nacional de Investigación Científica y Tecnológica, and IMARPE for their financial support, and would like to acknowledge grants awarded by the Inter-American Institute for Global Change Research in Montevideo (GEO-0452325, EXA 470/10, PIP 12-201101-00892; CRN3070), as well as the Ministerio de Ciencia, Tecnología e Innovación Productiva in Argentina (FONCyT 01553, FONCyT PICT 2006 No. 1553). Funding was provided by NOAA Fisheries through the Northwest and Southwest Fisheries Science Centers. The CSIC research was supported by projects P07-RNM-02976 (Junta de Andalucía), CTM2011-22856 (Spanish Ministry of Science and Innovation) and 2019AEP203 (CSIC).Peer reviewe

Climate Change Vulnerability of Freshwater Fishes of the San Francisco Bay Area

Climate change is expected to progressively shift the freshwater environments of the San Francisco Bay Area (SFBA) to states that favor alien fishes over native species. Native species likely will have more limited distributions and some may be extirpated. Stream-dependent species may decline as portions of streams dry or become warmer due to lower flows and increased air temperatures. However, factors other than climate change may pose a more immediate threat to native fishes. Comparison of regional vs. statewide vulnerability (baseline and climate change) scores suggests that a higher proportion (56% vs. 50%) of SFBA native species, as compared to the state’s entire fish fauna, are vulnerable to existing anthropogenic threats that result in habitat degradation. In comparison, a smaller proportion of SFBA native species are vulnerable to predicted climate change effects (67% vs. 82%). In the SFBA, adverse effects from climate change likely come second to estuarine alteration, agriculture, and dams. However, the relative effect of climate change on species likely will grow in an increasingly warmer and drier California. Maintaining representative assemblages of native fishes may require providing flow regimes downstream from dams that reflect more natural hydrographs, extensive riparian, stream, and estuarine habitat restoration, and other management actions, such as modification of hatchery operations

Effects of Climate Change on the Inland Fishes of California: With Emphasis on the San Francisco Estuary Region

California’s native inland fish fauna is in steep decline, a pattern which is reflected in the status of fishes native to streams flowing into the San Francisco Estuary and in the estuary itself. Climate change will further reduce the distribution and abundance of these mostly endemic fishes and expand the distribution and abundance of alien fish species. The decline and likely extinction of many native fishes reflects dramatic shifts in the state’s aquatic ecosystems; shifts which are being accelerated by climate change. Fishes requiring cold water, such as salmon and trout, will especially suffer from climate change impacts of warmer water and reduced summer flows. Additionally, desirable species living in the San Francisco Estuary and the lower reaches of its streams will have to contend with the effects of rising sea level along with changes in flows and temperature. This paper: (1) briefly describes the environment of California and its fish fauna, (2) summarizes the projected general effects of climate change on its aquatic environments, (3) discusses likely interactions of climate with other stressors of fish populations, (4) describes possible effects on fishes of the San Francisco Estuary, and (5) suggests elements of a conservation strategy for the native fish fauna, focusing on the San Francisco Estuary

Projected Effects of Future Climates on Freshwater Fishes of California

A methodology is presented that allows systematic evaluation of climate change impacts on freshwater fishes in California (121 native fish taxa and 43 aliens). The methodology uses expert opinions of the authors and literature reviews of status and biology of the fishes to score both status of each species (“baseline vulnerability”) and likely impact of climate change (“climate change vulnerability”). Baseline and climate change vulnerability scores were highly correlated with one another and were consistent among different scorers. Native species were found to have both greater baseline and greater climate change vulnerability than alien species. Fifty percent of natives had critical or high baseline vulnerability versus none for aliens; 83 percent had critical or high climate change vulnerability versus 19 percent for aliens. Fishes with high baseline vulnerability were also likely to have highest vulnerability to climate change. These results show that predicted climate change effects on fresh water environments will dramatically change the fish fauna at all scales and at all elevations. The research team concluded that most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction, if present trends continue. Fishes requiring cold water

Projected Effects of Future Climates on Freshwater Fishes of California

A methodology is presented that allows systematic evaluation of climate change impacts on freshwater fishes in California (121 native fish taxa and 43 aliens). The methodology uses expert opinions of the authors and literature reviews of status and biology of the fishes to score both status of each species (“baseline vulnerability”) and likely impact of climate change (“climate change vulnerability”). Baseline and climate change vulnerability scores were highly correlated with one another and were consistent among different scorers. Native species were found to have both greater baseline and greater climate change vulnerability than alien species. Fifty percent of natives had critical or high baseline vulnerability versus none for aliens; 83 percent had critical or high climate change vulnerability versus 19 percent for aliens. Fishes with high baseline vulnerability were also likely to have highest vulnerability to climate change. These results show that predicted climate change effects on fresh water environments will dramatically change the fish fauna at all scales and at all elevations. The research team concluded that most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction, if present trends continue. Fishes requiring cold water

Climate change vulnerability of native and alien freshwater fishes of California: a systematic assessment approach.

Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a systematic assessment approach that incorporates expert knowledge was developed to determine status and future vulnerability to climate change of freshwater fishes in California, USA. The method uses expert knowledge, supported by literature reviews of status and biology of the fishes, to score ten metrics for both (1) current status of each species (baseline vulnerability to extinction) and (2) likely future impacts of climate change (vulnerability to extinction). Baseline and climate change vulnerability scores were derived for 121 native and 43 alien fish species. The two scores were highly correlated and were concordant among different scorers. Native species had both greater baseline and greater climate change vulnerability than did alien species. Fifty percent of California's native fish fauna was assessed as having critical or high baseline vulnerability to extinction whereas all alien species were classified as being less or least vulnerable. For vulnerability to climate change, 82% of native species were classified as highly vulnerable, compared with only 19% for aliens. Predicted climate change effects on freshwater environments will dramatically change the fish fauna of California. Most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction. Fishes requiring cold water (<22°C) are particularly likely to go extinct. In contrast, most alien fishes will thrive, with some species increasing in abundance and range. However, a few alien species will likewise be negatively affected through loss of aquatic habitats during severe droughts and physiologically stressful conditions present in most waterways during summer. Our method has high utility for predicting vulnerability to climate change of diverse fish species. It should be useful for setting conservation priorities in many different regions