PARENT SESSION
Contributed Oral Session 56: Aquatic Ecology: Communities
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 513 C, Level 5, Palais des congrès de Montréal

Hypoxia and life history variation in a mouth brooding cichlid.

Reardon, Erin ^*,1, Chapman, Lauren ^{1, 2}, ¹ Department of Biology, Montreal, QC, H3A 1B1² Wildlife Conservation Society, Bronx, NY, USA

ABSTRACT- Despite the widespread nature of hypoxia (oxygen scarcity) in fresh waters and increasing levels associated with anthropogenic influences worldwide, little is known about reproductive costs of oxygen scarcity for fishes. The goal of this study was to explore potential costs of reproduction under hypoxia in the mouth brooding African cichlid Pseudocrenilabrus multicolor victoriae. Brooding and non-brooding female P. multicolor were collected from six sites in Uganda that represented a range of dissolved oxygen (DO) concentrations. For each population, we estimated size at maturity and brood quality metrics (number of eggs, egg volume, and egg energy content). In a laboratory growth experiment, we raised F1s from multiple families of four field populations using a split brood design. We quantified metabolic rates of brooding and non-brooding females and males in addition to the suite of reproductive traits measured for field populations. In the field, P. multicolor was found to breed successfully under conditions of extreme hypoxia. Across populations, broods raised under hypoxia had a smaller size at maturity and produced larger eggs indicating a degree of environmentally-induced variation in reproductive traits. Flexibility in life-history traits in response to divergent oxygen environments may contribute to the widespread distribution of P. multicolor and to its demographic dominance in many East African swamps.

Key words: fish reproduction, oxygen, Africa, swamps