The Extent and spatial scale of connectivity among reef fish populations: implications for marine protected areas designated for fisheries enhancement

Enthusiasm for the use of no-take marine protected areas (MPAs) as management tools for the protection and enhancement of coral reef fishes is widespread. However, evidence that such marine reserves actually enhance fishery yields is limited, primarily because of difficulties in quantifying the exchange of individuals—especially larvae—between local populations within and outside the protected area. Knowledge of the extent and spatial scale of this connectivity is of vital importance for the effective design and implementation of marine reserves intended as fishery management tools. We review our current understanding of connectivity among coral reef populations, including the role of important determining factors such as pelagic larval duration, larval behavior, and hydrodynamics. We also discuss artificial and natural tagging methods that potentially can be used to track movements of larvae between marine reserves and surrounding waters. To illustrate the application of such methods, we discuss ECONAR (Ecological CONnections Among Reefs), a new, regional-scale research project designed to measure the extent of connectivity among populations of coral reef fishes in the Mesoamerican Barrier Reef System

Biological Invasion Theory: Darwin's Contributions from The Origin of Species

Support for this work was provided by (1) a Federal Aid in Sport Fish Restoration Project F-69-P (to R. A. Stein), administered jointly by the US Fish and Wildlife Service and Ohio Department of Natural Resources-Division ofWildlife, (2) the Department of Evolution, Ecology and Organismal Biology at The Ohio State University (OSU), and (3) a Presidential Fellowship awarded to S. A. Ludsin by OSU

First-Year Recruitment of Largemouth Bass: The Interdependency of Early Life Stages

Four early life events (i.e., hatching, the ontogenetic diet shift to piscivory, fall lipid accumulation, and the first winter) are conceptualized as being critical to 1st-yr recruitment success of largemouth bass (Micropterus salmoides) via cause-and-effect associations among them. Toward this end, we conducted a multiple life-stage investigation of largemouth bass to examine the functional dependency and significance to recruitment of these temporally separated early life events. Specifically, we quantified growth and survival of two largemouth bass year-classes in six Alabama ponds from hatching to the end of the first winter. The first winter was an important survival bottleneck with lower largemouth bass survival in ponds with smaller largemouth bass (high-density ponds), relative to ponds with larger fish (low-density ponds). While cannibalism was not important, we found sizedependent first-winter mortality to be regulated directly by lipid reserves (i.e., triglycerides) accumulated during fall, and indirectly by both hatch date and the ontogenetic diet shift to piscivory during summer. Early-hatched largemouth bass attained an initial length advantage, remaining large relative to late-hatched fish, despite the relatively higher growth rate of late-hatched fish during their first month of life. Enhanced size permitted earlyhatched fish to become piscivorous before late-hatched fish, increasing their access to fish prey (i.e., sunfishes) during fall. This in turn elevated their fall lipid accumulation and winter survival above that of late-hatched fish. Our results indeed suggest that 1st-yr recruitment of largemouth bass in southern systems is governed by several functionally dependent critical events. Because each is likely vital to understanding recruitment variability, we suggest that future recruitment studies should adopt a more synthetic (i.e., multiple life-stage) approach.This research was supported in part by National Science Foundation grants DEB-9108986 and DEB-9410323, and Federal Aid in Fish Restoration Project F40-R administered by the Alabama Game and Fish Division to DRD

First-Summer Survival of Largemouth Bass Cohorts: Is Early Spawning Really Best?

Previous work has demonstrated that survival of largemouth bass Micropterus salmoides through the first year of life can be size dependent, favoring larger individuals. Because size, diet biomass, lipid accumulation, and ultimately overwinter survival of juveniles are typically positively related to age, early spawning is clearly advantageous. However, a true understanding of which largemouth bass cohorts contribute to the new year-class remains somewhat unclear because these conclusions have largely been based upon fish collected during summer rather than fish collected during spring. Conceivably, even earlier hatched cohorts of largemouth bass could have existed in many of these studies, and these fish may simply not have survived to the summer collection period. In order to assess this possibility, we quantified first-summer survival of largemouth bass cohorts collected during 1992 and 1993 in Auburn, Alabama, ponds (which were 2–5 ha each). Our results indicate that it is early-hatched cohorts that likely contribute to the new year-class. Although we found that early-hatched cohorts were lost between May and July, these losses were not attributable to age-dependent mortality; instead, sampling biases associated with avoidance of seines by older, larger young-of-year largemouth bass appear to have driven these shifts. In addition, because we found that size-dependent cannibalism during summer acted to remove smaller, later-hatched largemouth bass, early hatching may enhance survival during larval and early juvenile stages in southern systems (and not just during the winter period). Given this information, fishery managers may potentially be able to implement harvest regulations that are designed to protect large, early-spawning adults, thereby increasing the probability of producing a strong year-class by enhancing first-summer growth and, ultimately, recruitment to adult stages.This research was supported in part by National Science Foundation grants DEB-9108986 and DEB-9410323 and Federal Aid in Sport Fish Restoration project F40-R (administered by the Alabama Game and Fish Division to D. R. DeVries)

Life After Death in Lake Erie: Nutrient Controls Drive Fish Species Richness, Rehabilitation

We explored the recent (1969–1996) dynamics of fish communities within Lake Erie, a system formerly degraded by eutrophication and now undergoing oligotrophication owing to phosphorus abatement programs. By merging bottom trawl data from two lake basins of contrasting productivity with life-history information (i.e., tolerances to environmental degradation, diet and temperature preferences), we examined (1) the relationship between system productivity and species richness, (2) whether fish communities are resilient to eutrophication, and (3) whether oligotrophication necessarily leads to reduced sport and commercial fish production. Reduced phosphorus loading has led to fish community rehabilitation. In the productive west basin, six species tolerant of eutrophy (i.e., anoxia, turbidity) declined in abundance, whereas the abundance of three intolerant species increased through time. In the less productive central basin, although only one tolerant species declined, four species intolerant of eutrophic conditions recovered with oligotrophication. These differential responses appear to derive from dissimilar mechanisms by which reduced productivity alters habitat and resource availability for fishes. Specifically, enhanced bottom oxygen, combined with reduced biogenic turbidity and sedimentation, likely drove the loss of tolerant species in the west basin by reducing detrital mass or the ability of these species to compete with intolerant species under conditions of improved water clarity. In contrast, reduced bottom anoxia, which enhanced availability of cool- and cold-water habitat and benthic macroinvertebrate communities, appears important to the recovery of intolerant species in the central basin. Ultimately, these productivity-induced shifts caused species richness to decline in Lake Erie’s west basin and to increase in its central basin. Beyond confirming that unimodal models of productivity and species diversity can describe fish community change in a recovering system, our results provide optimism in an otherwise dismal state of affairs in fisheries management (e.g., overexploitation), given that many recovering intolerant species are desired sport or commercial fishes.Support for this work was provided by (1) Federal Aid in Sport Fish Restoration F-69-P (to R. A. Stein), administered jointly by the U.S. Fish and Wildlife Service and ODNR-ODW, (2) the Department of Evolution, Ecology, and Organismal Biology at The Ohio State University, and (3) a Presidential Fellowship awarded to S. A. Ludsin by The Ohio State University

Benefits of Turbid River Plume Habitat for Lake Erie Yellow Perch (Perca flavescens) Recruitment Determined by Juvenile to Larval Genotype Assignment

Nutrient-rich, turbid river plumes that are common to large lakes and coastal marine ecosystems have been hypothesized to benefit survival of fish during early life stages by increasing food availability and (or) reducing vulnerability to visual predators. However, evidence that river plumes truly benefit the recruitment process remains meager for both freshwater and marine fishes. Here, we use genotype assignment between juvenile and larval yellow perch (Perca flavescens) from western Lake Erie to estimate and compare recruitment to the age-0 juvenile stage for larvae residing inside the highly turbid, south-shore Maumee River plume versus those occupying the less turbid, more northerly Detroit River plume. Bayesian genotype assignment of a mixed assemblage of juvenile (age-0) yellow perch to putative larval source populations established that recruitment of larvae was higher from the turbid Maumee River plume than for the less turbid Detroit River plume during 2006 and 2007, but not in 2008. Our findings add to the growing evidence that turbid river plumes can indeed enhance survival of fish larvae to recruited life stages, and also demonstrate how novel population genetic analyses of early life stages can contribute to determining critical early life stage processes in the fish recruitment process

Evidence of hypoxic foraging forays by yellow perch ( Perca flavescens ) and potential consequences for prey consumption

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91146/1/FWB_2753_sm_fS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/91146/2/j.1365-2427.2012.02753.x.pd

Returning Sovereignty to the People

Governments across the world regularly invoke sovereignty to demand that the international community mind its own business while they commit human rights abuses. They proclaim that the sovereign right to be free from international intervention in domestic affairs permits them unfettered discretion within their territory. This Article seeks to challenge those proclamations by resort to sovereignty in the people, a time-honored principle that is typically more rhetorical than substantive. Relying on classical interpretations of sovereignty, this Article infuses substance into the concept of sovereignty in the people to recognize that a government is entitled to sovereign rights only as the legitimate representative of the people and only as long as it fulfills its duties to them. The Article then examines the conditions that must be met for a government to claim sovereign rights, as well as how and by whom access to these rights should be determined. Taken to its logical conclusion, sovereignty in the people establishes that (1) sovereign rights can be lost when governments commit less than the most egregious human rights abuses, which differentiates this from the responsibility to protect; and (2) any form of government is at risk of losing these rights, including democracies