Authors
Michael Bear, Barbara Lloyd
Abstract
The HMCS Yukon is a 366 ft. long former Canadian warship that was sunk in about 100 ft. of water off the coast of San Diego, California ( 32.7800, -117.2853) in 2000 to act as an artificial reef. The first scientific study of the marine life on the Yukon was done in 2005 by the San Diego Oceans Foundation and Dr. Ed Parnell of Scripps Institution of Oceanography.
This study will document the current changes in the marine biodiversity that has colonized the shipwreck since the previous study. High resolution cameras and iNaturalist , a citizen science app which is maintained by the California Academy of Sciences, were used to inventory the taxonomic diversity of marine life on the HMCS Yukon as of 2020.
Introduction
In 2000, The HMCS Yukon, a 366 ft. long former Canadian warship was sunk in about 100 ft. of water off the coast of San Diego to act as an artificial reef. The first scientific study of the marine life associated with the Yukon was done in 2004 by the San Diego Oceans Foundation and Dr. Ed Parnell of Scripps Institution of Oceanography. In 2003, the authors as well as several other advanced divers, were invited to be some of the early Yukon Research Divers after it sank.
Parnell (2004), used a program consisting of volunteer divers to conduct fish counts on permanently established transect lines, as well as photographing quadrats attached to the hull and deck. No data were collected inside the vessel for safety reasons. The volunteer program was successful as a pilot program for implementing fish and invertebrate studies using trained volunteers. The results indicated that fish count data were consistent among the most experienced fish counters. However, because the study was voluntary, sampling effort was random.”.3
A major disadvantage of this method was that, with the exception of one or two quadrates which were photographed on a semi-regular basis, most of the data were collected by divers trained in visual recognition of fish species—a method which is only as good as the divers’ fish ID training. Some divers were better at species recognition than others, so this affected the quality of the data obtained by this method.
Parnell says about this study, “One of the greatest concerns for the monitoring project was the accuracy and precision of the divers (Parnell, 2004). This is a serious concern for professional research divers and is of even greater concern for volunteer divers. This issue has been addressed in a rigorous study in Florida that was specifically designed to test the abilities of trained volunteer divers to record environmental parameters and to count fish (Halusky et al. 1994). The divers were able to successfully record most of the environmental parameters, but there were many problems with the fish counts that were attributed to insufficient training and variable levels of skill among the divers.”4
And, this is to say nothing of variable conditions on the ship, which included low visibility, strong currents and depth-related narcosis.
Despite these disadvantages, quite a bit of data was collected and analyzed during this period, concerning both vertebrates and invertebrates. 5
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