The effects of climate change on the ecology of fishes

Abstract

Ocean warming and acidification are set to reshuffle life on Earth and alter ecological processes that underpin the biodiversity, health, productivity, and resilience of ecosystems. Fishes contribute significantly to marine, estuarine, and freshwater species diversity and the functioning of marine ecosystems, and are not immune to climate change impacts. Whilst considerable effort has been placed on studying the effects of climate change on fishes, much emphasis has been placed on their (eco)physiology and at the organismal level. Fishes are affected by climate change through impacts at various levels of biological organisation and through a large variety of traits, making it difficult to make generalisations regarding fish responses to climate change. Here, we briefly review the current state of knowledge of climate change effects on fishes across a wide range of subfields of fish ecology and evaluate these effects at various scales of biological organisation (from genes to ecosystems). We argue that a more holistic synthesis of the various interconnected subfields of fish ecology and integration of responses at different levels of biological organisation are needed for a better understanding of how fishes and their populations and communities might respond or adapt to the multi-stressor effects of climate change. We postulate that studies using natural analogues of climate change, meta-analyses, advanced integrative modelling approaches, and lessons learned from past extreme climate events could help reveal some general patterns of climate change impacts on fishes that are valuable for management and conservation approaches. Whilst these might not reveal many of the underlying mechanisms responsible for observed biodiversity and community change, their insights are useful to help create better climate adaptation strategies for their preservation in a rapidly changing ocean.

Are fish immunocompetent enough to face climate change?

“…Considering the current forecasts of climate change, hypoxia is predicted to become more widespread with more drastic seasonal declines, especially in shallow coastal waters, while pathogen abundance and virulence are increasing in warmer waters. The potential effects of hypoxia as a climate change stressor on fish immunocompetence, adaptability and migration behaviour remain severely understudied [ 112 ]. Future research should focus on the sensitivity of early life stages and the adaptive potential of different fish species to hypoxic conditions in trans-generational experiments at predicted environmental conditions (including spatial and temporal variabilities such as cycling oxygen levels) to better evaluate fish disease resistance and immunocompetence (see §§4 and 5).…”

Ecological generalism and physiology mediate fish biogeographic ranges under ocean warming

“…Species can respond to environmental disturbances in varying ways [ 5 ]. They can relocate to new environments [ 6 ], physiologically acclimate [ 7 ] and/or genetically adapt [ 8 ] to avoid the consequence of demographic collapse or extinction [ 9 ].…”

Effects of Water Temperature and Structural Habitat Complexity on the Routine Swimming Speed and Escape Response of Post-Settlement Stage White Seabream

“…The increasing warming of the seawater surface will most certainly alter coastal landscapes, with far-reaching consequences for the structure and function of marine ecosystems and organisms [12,13]. Here, we investigated the effects of increased water temperature and decreased structural habitat complexity on the routine swimming speed and escape response of post-settlement stage white seabream, Diplodus sargus (Linnaeus 1758).…”