TABLE 1 Number of visual and acoustic detections of cetacean groups (and individuals) from the Ewing during the L-DEO survey off the Pacific coast of Costa Rica, Nicaragua, and Gulf of Fonseca (a) Species Visual-Only Acoustic-Only Sightings Detections Tursiops truncatus 6 (50) -- Stenella attenuata 5 (38) -- Stenella longirostris -- -- Delphinus delphis
1 (45) -- Delphinus sp.
Growth and reproduction of female short-beaked common dolphins, Delphinus delphis
, in the eastern tropical Pacific.
The 8 species were the short-beaked common dolphin (Delphinus delphis
), long-beaked common dolphin (D.
In the 2,258 fishing trips monitored up to that point, only 8.7 percent encountered dolphins (delphinus delphis
) and in only 91 cases did some form of interaction occur.
For example, recent DNA studies of what was thought to be a single species, the common dolphin (Delphinus delphis
), revealed the existence of two species, now known as the short-beaked common dolphin (D.
These include the turtles Chelonia mydas and Lepidochelys olivacea; the dolphins Delphinus delphis
and Tursiops truncates, and also the tunicate Pyura praeputialis.
These surveys provided comprehensive estimates of abundance for short-beaked common dolphin (Delphinus delphis
) in the California Current.
This assertion is consistent with documented correlations between water temperature fluctuations (associated with La Nina events) and short-beaked common dolphin (Delphinus delphis
) distribution (Neumann, 2001) and distributional range limits for some Delphinidae species determined by water temperature (Gaskin, 1968).
About 30 cetacean species within the Delphinidae, Ziphiidae, Physeteridae, Kogiidae and Balaenopteridae inhabit or are expected to be found in the Pacific and Caribbean economical waters of Costa Rica (May-Collado in press), According to Gerrodette and Palacios (1996) Delphinus delphis
, Stenella coeruleoalba, beaked whales (Ziphiidae), and Tursiops truncatus are the most abundant cetaceans in Costa Rican Pacific waters.
Common dolphins (Delphinus delphis
) stranded off the California coast from 1995 to 1997 were shown to have morbilliviral infection by virus neutralization and enzyme-linked immunosorbent assay (ELISA), as well as RT-PCR (9).
Bottlenose dolphin was the species most frequently sighted (43.4%, n schools = 221), followed by short-beaked common dolphin (Delphinus delphis
; 16.5%, n=84), and long-beaked common dolphin (Delphinus capensis; 12.4%, n=63; Table 2).
4-19% for short-beaked common dolphins (Delphinus delphis
) (Pilleri, 1970; Dailey and Walker, 1978), 0.2% vs.
Gulls, shearwaters, and pelicans were often found foraging with short-beaked and long-beaked common dolphins (Delphinus delphis