Reoccurrence of the Pacific Seahorse
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Two events may account for the appearance of Hippocampus in San Diego Bay in recent years: a local warm water intrusion and changes in sewage disposal. The anomolous warming of local coastal water during the latest 'El Nino' event in 1982-83 (McGowan 1983) could have reestablished larvae or adults in San Diego Bay from the southern populations, The previous warming in southern California, 1957-1959, could account for the earlier mentioned 1958 and 1962 seahorse records (Hubbs and Hinton 1963). The fact that the first specimen in 1984 was found on an open ocean beach lends support to this hypothesis.

The health of the eelgrass habitat inside San Diego Bay has been improved by the elimination of direct sewage discharge and restrictions on other pollutants entering San Diego Bay within the last decade or so.

The potential for successful reproduction is plausible considering that two specimens caught near Harbor Island Marina subsequently released young in aquaria (C. Jantsch, pers. comm., 1986). The seahorses kept at the Scripps Aquarium also released young. A large female specimen which was donated to the Scripps Aquarium in July 1986, after five months in captivity, was gravid. Two pairs of smaller specimens currently residing at the Scripps Aquarium court frequently and remain as distinct pairs. The females are too small to produce many eggs, indicating that they are young individuals, possibly spawned in San Diego Bay.