Population Biology Commons^™

A Preliminary Assessment Of The Spawning Potential Ratio Of Five Target Species Of The Coastal Gillnet Fishery In Guyana And Suriname, Tomas Willems, Elford Liverpool, Michael Hiwat

Gulf and Caribbean Research

Data—limited stock assessment methods have the potential to positively impact livelihoods of fishermen around the world by providing management recommendations that aim to optimize sustainable yields from fisheries. Some years ago, a novel length— based (LB) method was developed for the assessment of spawning potential ratio (SPR), a measure of the reproductive capacity of fish stocks. We applied the LB—SPR method to 5 important target species of the coastal gillnet fishery in Guyana and Suriname. Nebris microps (Smalleye Croaker; 32% SPR) and Macrodon ancylodon (King Weakfish; 34% SPR) had the highest spawning potential, but remained below the 40% target level …

Investigation Of Dead Ocean Quahogs (Arctica Islandica) Shells On The Mid-Atlantic Bight Continental Shelf, Alyssa Leclaire

Master's Theses

Ocean quahogs, Arctica islandica, are a long-lived, widely dispersed, biomass dominate in the Mid-Atlantic; therefore, quahog shells are valuable resources for studying climate change over time. Recently, dead ocean quahog shells were discovered south and inshore of the present biogeographic range of this animal. The presence of ocean quahog shells outside the current range is presumably a consequence of past regressions and transgressions of the Cold Pool, the bottom-trapped, cool body of water that allows boreal animals to live at lower latitudes. Dead ocean quahog shells were collected offshore of the DelMarVa Peninsula then radiocarbon-dated, evaluated for taphonomic condition, …

Disturbance Ecology Of The Sonadora River Rock Pool Insect Assemblage At Luquillo Experimental Forest, Puerto Rico, Patrick Gilkey

Master's Theses

Freshwater rock pools can serve as habitat for aquatic insects. Flash-flooding can have profound effects on insect communities in streams and rivers, but these effects have not been studied on freshwater rock pools. The goal of this thesis was to describe ecological patterns of the Sonadora River rock pool insect community at the Luquillo Experiment Forrest, Puerto Rico, specifically in response to intense flash-flooding, and then perform experiments to elucidate possible processes to explain those patterns. The rock pools contained primarily three taxa of Dipteran (true-fly) larvae, in order of decreasing abundance, 1) a newly discovered species of ceratopogonid (biting …

An Examination Of The Influence Of Multi-Scale Processes And Connectivity On The Population And Assemblage Dynamics Of Headwater Fishes, Josh P. Hubbell

Dissertations

Typified by their branching pattern, headwaters are numerically abundant as the density of these habitats increases with increasing distance from the base of a dendritic river system. Connectivity among headwaters is complex, resulting in the spatial isolation of populations. Headwater specialists have evolved a suite of traits that permit these species to permanently reside within these habitats. The spatial configuration and connectivity of headwaters has repercussions for metapopulations and meta-assemblages. I investigated how multi-scale processes and connectivity influenced the patch occupancy, coexistence, movement ecology, population structure, and gene flow of headwater specialists. In chapter two, I used occupancy modeling to …

Environmentally-Driven Variation In The Population Dynamics Of Gulf Menhaden (Brevoortia Patronus), Grant D. Adams

Master's Theses

Gulf Menhaden (Brevoortia patronus) is an abundant forage fish distributed throughout the Northern Gulf of Mexico (NGOM). Gulf Menhaden support the second largest fishery, by weight, in the United States and represent a key linkage between upper and lower trophic levels. Variation in the population dynamics can, therefore, pose consequences for the ecology and economy in the NGOM. Here we aim to understand variation in the individual and population dynamics of Gulf Menhaden throughout ontogeny and how such variation relates to environmental processes. We utilized a suite of fishery-dependent and –independent, remote sensing, modeled, and in situ data …

Macrobenthic Communities In The Northern Gulf Of Mexico Hypoxic Zone: Testing The Pearson-Rosenberg Model, Shivakumar Shivarudrappa

Dissertations

The Pearson and Rosenberg (P-R) conceptual model of macrobenthic succession was used to assess the impact of hypoxia (dissolved oxygen [DO] ≤ 2 mg/L) on the macrobenthic community on the continental shelf of northern Gulf of Mexico for the first time. The model uses a stress-response relationship between environmental parameters and the macrobenthic community to determine the ecological condition of the benthic habitat. The ecological significance of dissolved oxygen in a benthic habitat is well understood. In addition, the annual recurrence of bottom-water hypoxia on the Louisiana/Texas shelf during summer months is well documented.

The P-R model illustrates the decreasing …