oviedo l. et al. (2011). critical foraging habitats of pantropical spotted dolphins (stenella...

7/28/2019 Oviedo L. et al. (2011). Critical foraging habitats of pantropical spotted dolphins (Stenella attenuata graffmani) in a tropical fjord: Golfo Dulce, Costa Rica. PPT Presentation. S

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Lenin E. Oviedo Correa1,2, David Herra-Miranda2, Juan Diego Pacheco-Polanco2,

Maria Gabriela Silva2 and Leszek Karczmarski1

1. Cetacean Ecology Lab. The Swire Institute of Marine Science, The University of Hong Kong

2. Vida Silvestre Golfo Dulce, Golfo Dulce Costa Rica

Critical Foraging Habitats of Pantropical Spotted

Dolphins (Stenella attenuata graffmani) in a Tropical

Fjord: Golfo Dulce, Costa Rica


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Lenin Enrique Oviedo Correa

PhD CandidateCetacean Ecology Lab

The Swire Institute of Marine Science

The University of Hong Kong


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Predictable Resources

Resident Communities

Small Areas

Predator Risk Reduced

Scramble Competition: High

Small Group Sizes

Variable Resources

Wide-Ranging Communities

Predator Risk High

Scramble Competition

reduced by

Cooperative Foraging

Large groups

Intermediate Communities

Habitat structure influences the energy acquisition and predation risk

Karczmarski et al 2005; Gowans, Wrsig, Karczmarski 2008


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Critical Habitats:Areas with properties that facilitatepopulation ecological fitness

Foraging

ForagingBreeding

LowHigh

Density

m3

m2

m1

1 - m2

1 m1Modified from Hoyt (2011)


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The identification of critical habitats for local cetacean fauna

represents the basis of the design and implementation of

Marine Protected Areas.

Dolphin Foraging Habitat Assessment off Osa

Peninsula and Golfo Dulce, Costa Rica


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Costa

Rica

Golfo Dulce: Tropical Fjord

Eastern

TropicalPacific

Golfo Dulce DEM by Amaru Marques Artavia


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Sightings data were collected opportunistically off Osa

Peninsula (2001-2006, n= 1247) and through systematic

surveys in Golfo Dulce (2005-2011, n= 102).

Oviedo et al (2009) REVMAR


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Regional (meso) scale S. a. graffmani

GIS + NNI + Kernel Density Estimate




Regional (meso) scale S. a. graffmani

GIS + NNI + Kernel Density Estimate


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Regional (meso) scale S. a. graffmani Local (fine) scale S. a graffmani

GIS + NNI + Kernel Density Estimate Behavior + Spatiotemporal Patterns





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Objectives:

Identify areas of critical importance to dolphins (application of

behavioral and spatial ecology)

Contribute to an ecosystem based framework that integrates

the current needs of non consumptive use of resources

Regional (meso) scale S. a. graffmani Local (fine) scale S. a graffmani

GIS + NNI + Kernel Density Estimate Behavior + Spatiotemporal Patterns





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Non-random clustered aggregations throughout the study area

Analyses: only records with effort > 3.97 hours

Relative Density

Spatial Pattern of pantropical spotted dolphins

NNI Z score p value PatternOsa 0.35 -44.08 < 0.01 Clustered

Osa Rainy 0.53 -21.36 < 0.01 Clustered

Osa Dry 0.41 -29 < 0.01 Clustered

GD 0.72 -5.43 < 0.01 ClusteredGD Rainy 0.76 -3.31 < 0.01 Clustered

GD Dry 0.72 -3.31 < 0.01 Clustered

Oviedo et al (in rev) Critical foraging habitat of pantropical spotted dolphins in Golfo Dulce, Costa Rica


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Osa Peninsula: density and group sizes vary with season(Kruskal Wallis= X2: 6.98; p < 0.05)

Golfo Dulce: density and group sizes stable across the year

(Kruskal Wallis= X2: 0.091; p > 0.05)

DryRainy

Oviedo et al (in rev) Distribution of pantropical spotted dolphins off the Southern Pacific of Costa Rica

Relative Density


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Golfo Dulce: homogenous coverage of the inner basin

during group follows

Group Follow and Behavior Sampling



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Dolphins spend most of their time searching and capturing prey


0

10

20

30

40

50

60

Forage Travel Social Rest Mill

%Occurrence

Rainy Dry First Encounter


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Non random cluster of foraging dolphins during group follow per

season


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Critical Foraging Habitat: Golfo Dulce

Important core (critical) areas where the occurrence of foraging

bouts is intense: Associated with river drainage systems and with

aggregations of most important prey ballyhoo (Hemiramphus sp.)

DryRainy



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We have identified areas and habitats that are structurally

critical to the sustainability of a population of a semi-pelagic

dolphin within a complex inshore habitat

Critical core areas need for habitat protection

To preserve current spatiotemporal pattern of

animal-habitat relationship

Critical Habitats: Conservation and management

strategies

v


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How to conciliate the need for MPAs with non extractive

human activities for social benefits?

Important but non-critical areas might act as bufferzones where humans activities could continue but also

be monitored and managed

Licensing scheme for boats that may enter the areaswith high probability of dolphin encounters

Critical Habitats: Conservation and management

strategies


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Foraging is the dominant behavioral state within the activitybudget

The important occurrence of foraging bouts defines the inner

basin of Golfo Dulce as a critical habitat for energy intake

The habitat structure and patterns of aggregation provide an

empirical model of spatial distribution of dolphins with

mechanistic properties:

As foraging is behaviorally flexible response, it identifies therealized niche for pantropical spotted dolphins in the Golfo

Dulce region

In summary


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Strengthening the baseline ecological data as means toinform government decision makers

Socio-economic benefits of MPAs in Golfo Dulce:

Resource protection and management

Secure sources of revenue (dolphin watch operations)

Protecting and managing local fish stock for the needs ofboth dolphins and humans

Critical Habitats and Socio-Economic Needs


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Muchas Gracias

oviedo l. et al. (2011). critical foraging habitats of pantropical spotted dolphins (stenella...

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