The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Oceanographic processes driving the feeding ecology of franciscana dolphin off Southern Brazilian coast

Oceanographic processes driving the feeding ecology of franciscana dolphin off Southern Brazilian coast
Oceanographic processes driving the feeding ecology of franciscana dolphin off Southern Brazilian coast
The franciscana (Pontoporia blainvillei) is a coastal dolphin endemic to the south-western Atlantic Ocean. Incidental captures in fishing gillnets are the greatest conservation concern for this species. The present study examines the biophysical interactions between the franciscana prey composition and the marine environment. The feeding regime of franciscana was investigated from stomach contents of incidentally caught animals along the southern Brazilian coast. The characteristics of the franciscana habitat may reveal potential factors affecting the distribution and abundance of marine species, thus the franciscana prey (species number and size) was treated as a function of the oceanographic variables (sea surface temperature and chlorophyll-a), and the spatial (latitude and water depth), and temporal (season) parameters, through Linear and Generalized Linear Models (LM and GLM). Season and latitude were important predictors of the franciscana diet, followed by water temperature and depth. Chla parameter only influenced one fish species and therefore was not useful as an explanatory variable for our study. The influence of the predictors and prey distribution of the franciscana diet are similar to that found in the habitat by research cruise data. Some structures analysed (e.g. squid beaks) may remain longer in the stomachs. Therefore, the findings not only suggest a fairly opportunistic behaviour but it is likely that franciscana may occupy, and possibly for long periods, small spatial ranges. This behaviour might be a strategy for minimizing energetic costs by restricting movements to short distance areas, which can be an important factor for conservation planning along the southern Brazilian coast.
Cetacean, Environmental processes, Feeding ecology, Franciscana dolphin, GLM, Southwestern Atlantic ocean
0278-4343
Bassoi, M.
8791df9f-6fe4-48ed-bea8-4c90d309329b
Shepherd, J.g.
630dccd6-9f0b-4b70-aac9-feb3993fa0c9
Secchi, E.r.
4b11331a-8943-45e9-a969-980e1f560028
Moreno, I.b.
63e154dc-f658-470c-84a2-f7ba788b1696
Danilewicz, D.
10ab879d-47b5-4dc8-8172-ec14257e0cd3
Bassoi, M.
8791df9f-6fe4-48ed-bea8-4c90d309329b
Shepherd, J.g.
630dccd6-9f0b-4b70-aac9-feb3993fa0c9
Secchi, E.r.
4b11331a-8943-45e9-a969-980e1f560028
Moreno, I.b.
63e154dc-f658-470c-84a2-f7ba788b1696
Danilewicz, D.
10ab879d-47b5-4dc8-8172-ec14257e0cd3

Bassoi, M., Shepherd, J.g., Secchi, E.r., Moreno, I.b. and Danilewicz, D. (2020) Oceanographic processes driving the feeding ecology of franciscana dolphin off Southern Brazilian coast. Continental Shelf Research, 201, [104124]. (doi:10.1016/j.csr.2020.104124).

Record type: Article

Abstract

The franciscana (Pontoporia blainvillei) is a coastal dolphin endemic to the south-western Atlantic Ocean. Incidental captures in fishing gillnets are the greatest conservation concern for this species. The present study examines the biophysical interactions between the franciscana prey composition and the marine environment. The feeding regime of franciscana was investigated from stomach contents of incidentally caught animals along the southern Brazilian coast. The characteristics of the franciscana habitat may reveal potential factors affecting the distribution and abundance of marine species, thus the franciscana prey (species number and size) was treated as a function of the oceanographic variables (sea surface temperature and chlorophyll-a), and the spatial (latitude and water depth), and temporal (season) parameters, through Linear and Generalized Linear Models (LM and GLM). Season and latitude were important predictors of the franciscana diet, followed by water temperature and depth. Chla parameter only influenced one fish species and therefore was not useful as an explanatory variable for our study. The influence of the predictors and prey distribution of the franciscana diet are similar to that found in the habitat by research cruise data. Some structures analysed (e.g. squid beaks) may remain longer in the stomachs. Therefore, the findings not only suggest a fairly opportunistic behaviour but it is likely that franciscana may occupy, and possibly for long periods, small spatial ranges. This behaviour might be a strategy for minimizing energetic costs by restricting movements to short distance areas, which can be an important factor for conservation planning along the southern Brazilian coast.

This record has no associated files available for download.

More information

Accepted/In Press date: 11 April 2020
Published date: 1 October 2020
Keywords: Cetacean, Environmental processes, Feeding ecology, Franciscana dolphin, GLM, Southwestern Atlantic ocean

Identifiers

Local EPrints ID: 444434
URI: http://eprints.soton.ac.uk/id/eprint/444434
ISSN: 0278-4343
PURE UUID: eb35970d-650b-4e09-a314-489c8e8f4e31

Catalogue record

Date deposited: 19 Oct 2020 16:31
Last modified: 25 Nov 2021 17:16

Export record

Altmetrics

Contributors

Author: M. Bassoi
Author: J.g. Shepherd
Author: E.r. Secchi
Author: I.b. Moreno
Author: D. Danilewicz

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×