Variability in Fish Tissue Proximate Composition is Consistent with Indirect Effects of Hypoxia in Chesapeake Bay Tributaries

Abstract

The spatial and temporal extent of summer hypoxia (dissolved oxygen [DO] concentration ≤ 2 mg/L) in Chesapeake Bay and its tributaries has been increasing for decades, consequently affecting fish distribution and abundance by shifting biomass to non‐hypoxic habitats. Hypoxia in coastal waters impacts food web dynamics, thereby limiting ecosystem productivity and affecting regional fisheries. Additionally, laboratory studies of Atlantic Croakers Micropogonias undulatus have shown that hypoxia serves as an endocrine disruptor, reducing the production of the yolk precursor vitellogenin as well as affecting other biochemical pathways. Reproductive potential is therefore lower in hypoxia‐exposed Atlantic Croakers than in fish that are taken from normoxic conditions. We examined field‐caught Atlantic Croakers from three Chesapeake Bay tributaries with different DO levels to evaluate patterns in the lipid content of somatic and gonadal tissues. We found that somatic lipid content was not affected by the presence of hypoxia, whereas ovarian lipid content was significantly affected by the severity of hypoxia. Furthermore, Atlantic Croakers that were exposed indirectly to mild hypoxia (lasting hours to days) exhibited greater ovarian lipid content than fish that were captured from normoxic sites. As expected, severe hypoxia reduced the ability of Atlantic Croakers to accumulate lipids in their ovaries, likely affecting reproductive output. Stock assessment models that ignore the effects of hypoxia may yield overly optimistic production estimates for hypoxia‐exposed populations, particularly if environmentally invariant fecundity and growth are assumed.Received December 16, 2014; accepted September 24, 2015

Modeling the Population Effects of Hypoxia on Atlantic Croaker (Micropogonias undulatus) in the Northwestern Gulf of Mexico: Part 2—Realistic Hypoxia and Eutrophication

“…There is substantial field evidence that hypoxia has a negative effect on the reproductive output of croaker in the NWGOM (Thomas et al 2015;Rahman 2009, 2012). Recent measurements also showed a potential reproductive effect of hypoxia on croaker in the Chesapeake Bay (Tuckey and Fabrizio 2016). We use a 25% reduction in abundance (rather than higher) as our most likely estimate because our use of only of a few years from FVCOM limited how well we could represent intermediate and severe hypoxia years and the larger role played by direct mortality that can only be crudely represented on the kilometer and hourly resolution of the IBM.…”

Interdecadal changes in the community, population and individual levels of the fish fauna of an extensively modified estuary

“…; Cottingham et al ., ). Such findings are consistent with those for fish in other microtidal estuaries following the development of hypoxia in deeper waters (Howell & Simpson, ; Thiel et al ., ; Eby & Crowder, ; Tuckey & Fabrizio, ). Moreover, the smooth declining trends in A. butcheri production at the individual level over time (and so consistently for each of the 2+, 3+ and 4+ year classes), provide further evidence of negative effects on this species and suggest a more sustained habitat degradation [ i.e .…”

Resilience indicators support valuation of estuarine ecosystem restoration under climate change

“…). In another example, hypoxia influences egg characteristics of Atlantic croaker and acts as an endocrine disruptor that affects survival of young (Tuckey and Fabrizio ), with the potential to cause widespread failure of reproduction (Wu et al. , Thomas et al.…”

“…Recent research suggests that hypoxia reduces the immune response of oysters, rendering them more susceptible to disease (Breitburg et al 2015a), a factor that may have played a role in the near-complete collapse of oysters in the bay (Wilberg et al 2011). In another example, hypoxia influences egg characteristics of Atlantic croaker and acts as an endocrine disruptor that affects survival of young (Tuckey and Fabrizio 2016), with the potential to cause widespread failure of reproduction (Wu et al 2003, Thomas et al 2006, 2007, Landry et al 2007).…”