Stability in the feeding ecology of four demersal fish predators in the US Northeast Shelf Large Marine Ecosystem

Abstract

Evidence of species interactions are generally well understood over broad temporal and spatial scales, particularly for commercially valuable species. Yet species that are not as commercially valuable may nonetheless be ecologically important in stabilizing trophic interactions in large marine ecosystems. We examined the diets for 4 of these demersal fish species: black sea bass Centropristis striata, scup Stenotomus chrysops, Northern searobin Prionotus carolinus, and striped searobin P. evolans. We examined food habits data across size class, season, 5 yr time block, and geographic region to evaluate the major determinants of diet composition. We used multivariate statistics, specifically canonical correspondence analysis, as the primary method to explore diet determinants. Our results showed that the scup and 2 searobin species are primarily benthivorous, whereas black sea bass notably shifts towards piscivory with ontogeny. Our results also showed that the diet of these predators was mainly influenced by size class, region, and (to a lesser extent) season, whereas 5 yr time block did not notably influence diet composition, a surprising observation given the welldocumented changes to benthic habitat in this ecosystem. These results suggest that these species feed opportunistically in proportion to the relative abundance of available prey given the constraints of their morphology, which implies that despite notable impacts to benthic habitat, the prey field for these understudied species has been consistent (within seasonal variation) over the past 3 decades. Stable feeding dynamics such as these may act to enhance resilience in large marine ecosystems.KEY WORDS: Black sea bass · Scup · Northern searobin · Striped searobin · Benthic · Ontogenetic shifts · Northwest Atlantic · Canonical correspondence analysis 406: 239-250, 2010 thought to enhance stability of the food web, which can then enhance the stability and resilience of the entire system (Holling 1973). Predator-prey relationships may differ at different spatial and temporal scales and with varying degrees of disturbance. The scale at which these stabilizing mechanisms take place and the severity of disturbance may determine the extent to which the system can be managed, or at least its resilience for management assumptions, functionally speaking (Auster & Link 2009). Therefore, examining a system and the interactions with that system at the same scale at which it is managed is critical (Sherman 1991(Sherman , 1994(Sherman , 2006. Resale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESSMar Ecol Prog SerThe US Northeast Shelf (NES) LME has had an actively managed fishery for more than 3 decades and has experienced a wide range of impacts and disturbances (Fogarty & Murawski 1998, Garrison & Link 2000a,b, Link et al. 2008, Auster & Link 2009). These include fishing effects that directly (targeting) and indirectly (bycatch) impact populations, fishing effects that directly and indirectly impact benth...

You are what you eat, whenever or wherever you eat it: an integrative analysis of fish food habits in Canadian and U.S.A. waters

“…On initial examination, these results are in contrast to other studies that have detected significant seasonal or spatial differences in the fish diets (Garrison & Link, 2000 a ; Hovde et al , 2002; Jaworski & Ragnarsson, 2006; Bacha & Amara, 2009; Byron & Link, 2010). Yet some of these studies had a greater degree of prey resolution which affects the ability to detect differences.…”

“…Other studies that use a similar level of taxonomic resolution or were conducted in the same region as this study did result in the detection of seasonal and spatial differences in fish diet. These studies, however, used parametric multivariate methods such as correspondence analysis and canonical correspondence analysis which resulted in a low percentage of the variation in the data explained by the explanatory variables [Garrison & Link, 2000 a (12· 6–18· 4%); Jaworski & Ragnarsson, 2006 (8–16%); Byron & Link, 2010 (6· 2–12· 6%)]. Thus although the results were significant, they explained little of the variation in the data and did not fully consider the broader range of seasons and areas as in this study.…”

The role of sand lances (Ammodytes sp.) in the Northwest Atlantic Ecosystem: A synthesis of current knowledge with implications for conservation and management

“…Information from the literature revealed six additional fish species—American plaice ( Hippoglossoides platessoides , Pleuronectidae), Atlantic salmon ( Salmo salar , Salmonidae), Atlantic sturgeon ( Acipenser oxyrinchus oxyrinchus , Acipenseridae), offshore hake ( M. albidus , Merlucciidae), bluefin ( Thunnus thynnus , Scombridae) and yellowfin ( T. albacares, Scombridae) tunas, as well as northern shortfin ( Illex illecebrosus , Ommastrephidae) and longfin inshore ( Doryteuthis pealeii , Loliginidae) squids—consumed NWA Ammodytes in the region (Figure 4; Appendix S1: Supplemental 6). Six previously published studies used data from the NMFS trawl survey, but augmented sampling of certain species across seasonal periods including red ( U. chuss , Phycidae), offshore, silver and white hakes (Garrison & Link, 2000; Link, Lucey, & Melgey, 2012), little ( L. erinacea , Rajidae) and winter skates (Smith, Collie, & Lengyel, 2014), scup and black sea bass ( Centropristis striata , Serranidae) (Byron & Link, 2010), Atlantic mackerel and Atlantic herring (Suca et al, 2018), as well as summer flounder, bluefish, goosefish (Staudinger, 2004) and longfin inshore squid (Hunsicker & Essington, 2006). The remaining studies represented predator diets from inshore and estuarine habitats (Gelsleichter, Musick, & Nichols, 1999; Novak, Carlson, Wheeler, Wippelhauser, & Sulikowski, 2017; Wuenschel, Able, Vasslides, & Byrne, 2013), offshore areas of the continental slope and pelagic waters (Chase, 2002; Logan, Golet, & Lutcavage, 2015; Logan et al, 2011; Teffer, Staudinger, & Juanes, 2015), as well as Canadian waters (Carruthers, Neilson, Waters, & Perley, 2005; Dawe, Dalley, & Lidster, 1997; Hanson & Chouinard, 2002; Kelly & Hanson, 2013; Zamarro, 1992).…”

Diets of reef‐dwelling labrids (Choerodon species) vary with body size, season and habitat: influence of foraging ability, specialization and opportunism

“…The development of a range of multivariate methods (Clarke et al ., ) has greatly enhanced the ability to compare statistically the dietary compositions within and among species and identify the prey taxa that are responsible for any differences (Lek et al ., ; French et al ., ). These contemporary techniques facilitate comparisons between the relative extents to which the dietary composition for a species differs between habitats or environments, changes with increasing body size and responds to any seasonal variation in prey composition (Byron & Link, ; Platell et al ., ; Coulson et al ., ). A rigorous understanding of dietary compositions can also be used to predict the likely consequences of any changes in the composition of the prey or predator assemblages, brought about by anthropogenic factors, such as climate change, eutrophication and fishing (Langlois et al ., ; Smale et al ., ).…”