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Shark Conservation in Costa Rica

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Marine Protected Area Needed in Costa Rica

Marine Protected Area Needed in Costa Rica

Documenting Species in Sensitive Areas 

Our current research goal is to document and ultimately protect sensitive marine life in the Tropical East Pacific of Costa Rica. Through our local and international collaboration we are conducting a scientific census of fish, sharks and rays at two sites on the northwest coast of the Guanacaste region. Both sites host tremendous but undocumented biodiversity which is currently threatened by unregulated and expanding destructive fishing practices. The area has multiple user groups including fishers and divers competing for access to limited resources that garner direct and immediate economic benefits. Our long-term goal is to collect baseline ecological data and resource-user patterns to local fishery managers and communities for use in their public process of marine spatial planning and the creation of a marine protected area. 

Shark Eyes

Shark Eyes

Sharks eyes rival higher vertebrates in function and complexity. Sharks have mobile pupils that control the amount of light that enters the eye. There is tremendous diversity in the shape and orientation of shark pupils.

Size Variation

Size Variation

Do you ever wonder why some sharks are larger in some areas than in others? We attempted to find a hormonal basis to maximum size variation in a small hammerhead shark species.

Visual Fields

Visual Fields

Visual fields are the most fundamental aspect of vision. Here we determined the visual fields of four different ray and skate species and correlated them to their unique ecologies.

Cardinal Tetra

Cardinal Tetra

The cardinal tetra is the most important commercial species of ornamental fish exported from the Brazilian Amazon, contributing to about 80% of exports. Some 12-15 million wild specimens are legally exported annually and accounted by the Brazilian government. Here we examine ways to improve survivorship of these exported fish.

Cool Head

Cool Head

Have you ever wondered what it would be like to be a hammerhead shark? Why do they have the weird head shape and how does it impact the way they perceive their world? See part of the story here.

Ray Transport

Ray Transport

The cururu stingray, Potamotrygon histrix, are endemic freshwater stingrays from the middle region of the Rio Negro in the Brazilian Amazon basin and are exported worldwide as ornamentals caught by artisanal fishermen. The transport process from capture to final destination is long and stressful. This study quantified stress related changes in blood and water samples during a transport experiment which tested two water additives intended to increase survival.

Thyroid Review

Thyroid Review

Thyroid hormones have long been known to have regulatory roles in the differentiation and maturation of vertebrate embryos and proper development. Treatment with exogenous thyroid and corticoid hormones consistently promote development and reduce mortality rates in larval fishes, with potential hatchery- scale applications in aquaculture.

Color Vision

Color Vision

The potential for color vision in elasmobranchs has been studied in detail, however, a high degree of variation exists among the group. Evidence for ultraviolet (UV) vision is lacking, despite the presence of UV vision in every other vertebrate class. An integrative physiological approach was used to investigate color and ultraviolet vision in cownose rays and yellow stingrays, two batoids that inhabit different spectral environments.

Spectral Sensitivity

Spectral Sensitivity

The eyes of sharks rival those of higher vertebrates in structural and functional complexity and include a wide variety of functional adaptations. During their 400-million-year evolutionary history, sharks have radiated into nearly all oceanic and some freshwater habitats, thereby experiencing and adapting to variable ambient light conditions. In this study we examined the visual performance of several shark species from varying habitats.

Fish Vision

Fish Vision

Vision is a sense that brings near instantaneous information about the surrounding environment. The speed and quality of incoming visual information can be the difference between life and death to fish living underwater. In this study we examined the speed of visual processing and the color vision capacity of three predatory and prey fishes living within the Indian River Lagoon.

Hammerhead Visual Fields

Hammerhead Visual Fields

Several factors that influence the evolution of the unusual head shape of hammerhead sharks are proposed but few are empirically tested. In this study we tested the enhanced binocular field hypothesis (that proposes enhanced frontal binocular vision) by comparison of the visual fields of three hammerhead species with that of two more normal shaped sharks.