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Dolphins occur in a variety of coastal habitats,including fjords and close embayments. Specifically fjordbasins with their singular topography represent refugeareas to several dolphin populations, where key survivalactivities such as resting, socializing (including all aspects within a reproductive and nursing context) and feeding(including hunting) take place. Therefore, many of thosefjords contain critical habitats for resident populations ofdolphins, such as bottlenose dolphins (Tursiops  sp.) inDoubtful Sound (Fjorland, New Zealand), black dolphins(Cephalorhynchus eutropia ) in Chiloé Island (Chile), andthe dolphins inhabiting the so-called tropical fjords (semi-closed embayments with fjord-like oceanographic and

morphological characteristic) such as Saco doMamiraguá (Brazil) and Golfo Dulce (Costa Rica). Thosefjords sanctuaries are generally related with very isolatedlocations. However, even in the remoteness of thesehabitats the majority of threats to local dolphin populationscome from anthropogenic origins. Activities such asaquaculture and tourism are a common practice withinthese ecosystems given the relative stability of the aquaticenvironment and the scenery wealth that they hold.

The concept of critical habitat is yet to be fully appliedin marine conservation. It has served as a crucial modelin delineating core and buffer areas in Doubtful Sound(New Zealand). In this fjord, the location of critical areas

for resting are intended to be isolatedfrom boat traffic, as an effort to allocateprotection to the southernmostbottlenose dolphin population with anabrupt population decline. In Golfo Dulce

(Costa Rica) an on-going critical habitatassessment is intending to define the keyfeeding areas for two sympatric dolphin

36 JMBA Global Marine Environment

D O L P H I N C O N S E R V A T I O Nin fjord systems

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species; pantropical spotted dolphin (Stenella attenuata )and bottlenose dolphin. In this tropical fjord the mainthreats the to dolphin population are very similar to thosein Doubtful Sound; particularly the increase in boats traffic

due to tourism. At the moment preliminary results showthat dolphin feeding episodes are frequently interruptedby dolphin watching boats.

The use of these amazing landscapes in the touristindustry is unavoidable, since a great number of peopleare seeking to contemplate nature, especially in thesepristine ecosystems. Dolphin watching boats do notnecessarily have to become detrimental to dolphinsurvival; management actions can prevent pervasivenegative effects and can organize boat traffic. On theother hand, other human activities like aquacultureincrease the alteration of environmental condition in thewater column by pollution, thus modifying prey availability.More importantly aquaculture can limit spatially therequired niche for dolphins, a clear example is the musselfarming in Chiloé Island, this activity has limited andexcluded black dolphins from areas of potential use.

Fjords are complex coastal ecosystems, home ofmany amazing marine creatures such as dolphins. Theyshould remain pristine, while at the same time peopleshould have the possibility of admiring their spectacularbeauty, under a main premise: the impact on importantkey habitats should be lessened if not completely avoided,this includes a precautionary approach in cases wherethe effects on the ecosystem are yet to be known.

FURTHER READING

Hoyt E. 2005. Marine Protected Areas for whales, dolphins andporpoises: a world handbook for cetacean habitat conservation.Earthscan , U.K.

Lusseau, D. & Hinghan J.S.E. 2004. Managing the impact of dolphin-based tourism through the definition of critical habitats: the case ofbottlenose dolphins (Tursiops  spp.) in Doubtful Sound, New Zealand,Tourism Management 25, 657–667.

Lenin Oviedo1,2,3,4 and Juan Diego Pacheco Polanco 2,5

1) PROCMAR: Programa de Maestría en Ciencias Marina y Costeras,Universidad Nacional (UNA), Heredia Costa Rica 863000.

2) Fundación Vida Marina, Drake Bay, Costa Rica, www.vidamarina.org3) Proyecto Delphinus, Isla de Margarita, Venezuela.

4) Biotropica, Caracas Venezuela.E-mail: biotropica2@yahoo.com 

5) Escuela de Biología Universidad Nacional (UNA),Heredia Costa Rica.

JMBA Global Marine Environment 37

Also Published in JMBA

Oviedo L. 2007. Dolphin sympatric ecology in a tropical fjord:habitat partitioning by bathymetry and topography as a strategy tocoexist. JMBA, 87, xxx–xxx

Ribeiro, S., Viddi, F.A., Cordeiro J.L. & Freitas, T.R.O. 2007. Fine-scale habitat selection of Chilean dolphins (Cephalorhynchus eutropia ): interactions with aquaculture activities in southern ChiloéIsland, Chile. JMBA, 87, 119–128