Application of the nursery-role hypothesis to an estuarine fish

Abstract

In this paper, we address a recent article by Beck et al. (2001, Bioscience 51:633-641), in which it was proposed that the value of a juvenile fish habitat could be most efficiently measured as the production of adults from each juvenile habitat on a per area basis. Based upon retrospective microchemical analysis of otoliths, we calculated this metric (nursery value) for tidal freshwater and brackish littoral habitats of an estuarine fish, white perch Morone americana, in the Patuxent River estuary, Maryland (USA). In dominant year-classes of the population, brackish habitats had the highest nursery value, whereas in all other year-classes, freshwater habitats had the highest nursery value. This result highlights the importance of inter-annual variability in habitat use, and consequently presents a challenging trade-off for applying the nursery-role hypothesis to facilitate habitat conservation and management. Despite this limitation, the nursery-role hypothesis provides an enriched and much needed perspective on population connectivity.

Relative influence of habitat fragmentation and inundation on brown shrimp Farfantepenaeus aztecus production in northern Gulf of Mexico salt marshes

“…Coastal estuaries provide important nursery habitat for many commercially and recreationally important fish and shellfish species (Boesch & Turner 1984, Beck et al 2001, Kraus & Secor 2005. In the NGOM, the productivity of these species is linked to salt and brackish marsh habitat that is fragmenting and disappearing rapidly .…”

“…Several studies from the NGOM and elsewhere have documented a positive relationship between fishery landings and the extent of intertidal vegetation , Jackson et al 2001, Loneragan et al 2005. Vegetation provides increased foraging opportunities and shelter from predators , Beck et al 2001, Kraus & Secor 2005. Thus, the productivity of many species is tied to their ability to access intertidal vegetation (Weinstein 1979, Kneib 1997, that is, in turn, controlled by both the amount of edge habitat (intersection of vegetation and water) and the local pattern of inundation (Weinstein et al 2000, Minello et al 2003.…”

Availability, usage and expected contribution of potential nursery habitats for the California halibut

“…In fact, ranking nursery habitat value according to both the nursery-role concept (using density as a proxy) and expected contribution (EC) results in an almost complete reversal of trends (Unit-area production, estuary > lagoon > bay > exposed; EC, bay > exposed > lagoon > estuary). Kraus and Secor (2005) determined that there could also be reversals in nursery value rankings of freshwater and brackish habitats across years, and that dominant year classes of white perch, Morone americana, utilized juvenile habitat differently than all other year classes. These data present complications for applying the nursery-role concept of Beck et al (2001), but do not negate its worth as an objective metric of habitat value.…”

Tracking juvenile fish movement and nursery contribution within arid coastal embayments via otolith microchemistry

“…However, our results are not conclusive in terms of the contribution of specific embayment zones, due to our relatively small sample size (n = 27). Furthermore, PBE3 might contribute a significant number of recruits, but only during years in which a certain set of environmental conditions are met (Kraus & Secor 2005). Nevertheless, it is evident that the ability to evaluate habitat use and movement patterns over small spatial scales via elemental fingerprinting could have direct implications for the management of coastal embayments (see also Fodrie & Levin 2008).…”

“…A number of studies have examined nursery use along coastlines that receive large amounts of freshwater input, and include complex wetland and estuarine habitats extending over hundreds of square kilometers (Secor 1992, Thorrold et al 1998a, Kraus & Secor 2005. Researchers working in these systems have taken great care to document the incorporation of trace elements into otoliths as a function of elemental concentrations in water, salinity, temperature and fish growth rate (Fowler et al 1995, Secor et al 1995, as well as assessing intra-embayment variability in otolith composition (Thorrold et al 1998b).…”