Jenna Levich

Date of Award

2024

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Rycyk, Athena

Area of Concentration

Marine Biology

Abstract

As apex predators in the marine ecosystem, population declines in sharks can cause catastrophic imbalances leading to decreased biodiversity and eventual ecosystem collapse (Guida et al., 2016). Today, overfishing and unintentional bycatch are the leading causes of population declines in elasmobranchs and are so significant that the international union for conservation and nature (IUCN) quantifies approximately one-quarter of all elasmobranchs on the red list for threatened species (Guida et al., 2016). This study addresses this issue by examining the impact of two large-scale capture methods used within commercial fisheries. Longline and gillnet fishing operations subject many species of elasmobranchs to accidental bycatch and the impact of capture and release is typically not examined. Hematological indicators for stress response in 17 sharks subject to gillnet and longline capture were measured and quantified to determine the overall impact of capture method on shark survival and stress impacts. Alternative influential factors including species, sex, and maturity were compared across pH, lactate, and cortisol concentrations. Trends in stress response were observed across all 4 independent factors, but significant conclusions could not be drawn due to limitations in sample size and inaccuracies in stress quantification results.

Download

Share

COinS