Distribution of cetaceans in the offshore Gulf of Mexico

Abstract

In order to comprehend better the distribution of Gulf of Mexico cetaceans, all available records of whales and dolphins in the offshore Gulf were assembled and analysed. This included sightings, strandings ar.d captures of all species, except the Bottlenose Dolphin Tursiops truncatus, from all sources, except the recently completed GulfCet project. An attempt was made to confirm species identification for each of the records. A total of 1223 records was available for analysis. Twentyseven species of cetaceans have been confirmed to occur in the offshore Gulf of Mexico. All of the baleen whales, with the possible exception of the Bryde's Whale Balaenoptera edeni appear to be extralimital in the Gulf. The Sperm Whale Physeter macrocephalzis is, by far, the most common great whale in this body of water. All previous records of Common Dolphins Delphinus spp. in the Gulf are rejected as either incorrect or unreliable, and there is currently no convincing evidence that dolphins of the genus Delphinus occur in the Gulf. The Atlantic Spotted Dolphin Stenella frontalis is the only species, other than the Bottlenose Dolphin, that regularly occurs over the continental shelf. The Pantropical Spotted Dolphin Stenella attenuata is the most common species of small cetacean in oceanic waters of the Gulf, but many other species also occur there in significant numbers.

The most northern record of Gervais' beaked whale, Mesoplodon europaeus (Gervais, 1855), for the Southern Hemisphere

“…Species identification was based on the position of the two teeth in the lower jaw (Figures 2A and 2C), as well as through cranial measurements. The flattened laterally shape of the teeth ( Figure 2D) at mandibular symphysis, posteriorly located at middle length in the lower jaw ( Figure 2C), supported the identification (Raven, 1937;Rankin, 1956;Jefferson and Schiro, 1997). Additionally, the measurements of teeth and length of mandibular symphysis accounted for the correct identification of the specimen as M. europaeus.…”

A review of marine mammal records of Cuba

“…There are two unconfirmed reports of this species in the Gulf of Mexico, and it is possible that unidentified baleen whales from this region could be blue whales (Jefferson and Schiro, 1997). The only Caribbean record for this species is from near the Panama Canal in January 1922 (Harmer, 1923).…”

“…The range of the fin whale in the eastern North Atlantic extends from the Arctic ice edge to the Caribbean Sea and Gulf of Mexico (Gambell, 1985;Jefferson and Schiro, 1997). The fin whale may occur in coastal and oceanic waters near Cuba based on this species' known associations with continental shelf, slope, and oceanic waters throughout its range (e.g.…”

“…In the western North Atlantic, killer whales are known from the polar pack ice southward to Florida, the Lesser Antilles, and the Gulf of Mexico where they have been sighted year-round (Leatherwood et al, 1976;Jefferson and Schiro, 1997). In the Caribbean, killer whales have been recorded off Puerto Rico and the Virgin Islands, St. Vincent, Cayman Islands, Dominican Republic, Guadeloupe, Grenada, Trinidad and Tobago, St. Lucia, and Venezuela (Erdman, 1970; Caldwell et al, 1971a; Mignucci-Giannoni, 1989;1998; Boisseau et al, 2006;Rinaldi et al, 2006; Bolaños-Jiménez et al., 2008).…”

“…Alayo (1958) described this species as an occasional visitor to Cuba, and Varona (1973) reported that Gervais' beaked whales were often found off Cuba near Cayo Alacranes, Arroyo Bermejo, Cabañas, and Bahía Dominica. Although no sightings of this species have been documented in Cuban EEZ waters, several strandings have been recorded during November through April (Varona, 1985 (Varona, 1970(Varona, , 1985Jefferson and Schiro, 1997) (Figure 4). The oldest Cuban record of this species is a skull found in Cayo Alacranes in western Cuba (north of the Province of Pinar del Río) in November 1946 (Aguayo, 1954; Varona, 1970) (Figure 4).…”