The NMFS team just completed its annual juvenile shark survey in the Southern California Bight. This area is an important nursery ground for blue, mako, white and thresher sharks, all of which are caught in local fisheries. Blue and mako sharks are the two species most commonly caught during this survey although we do occasionally catch mola mola, pelagic rays and thresher sharks as well. Through the survey we collect a range of biological and fisheries data and also deploy satellite tags in collaboration with the TOPP program. Over the years satellite tags deployed from this cruise on blue and mako sharks have provided some incredible insights into the biology of both species revealing the importance of the California Current waters off both the US and Mexico as critical habitat. In fact six tags deployed last year on mako sharks are still transmitting. All have returned to or are close to the coastal waters of California and Mexico.

This year we plan to focus mainly on mako sharks.The makos have proven an excellent platform for SPOT tags, providing long-term records on movements patterns and hotspots both in and out of the California Current. In addition to tagging smaller animals, we will focus on getting tags out on larger mako sharks as well. While we know that the Bight and coast of Mexico are an important nursery ground for juvenile mako sharks, we don’t know where animals go once they leave this area. Continuing to tag the smaller animals is important for advancing the long-term database necessary to examine interannual differences and the impact of oceanography on movement patterns.

This years cruise is a little different from previous cruises in that we used longline vessel, The Ventura, captained by Pete Dupuy. In previous years we have used the R.V. David Star Jordon, a NOAA research vessel. While the fishing vessel is much smaller than the Jordon, a professional crew sets and retrieves the gear. Also, rather than using a cradle firmly attached to the stern, a stretcher is lifted over the side of the boat and the shark is tagged on deck. This is similar to the method used for salmon sharks.

This year’s cruise saw fewer mako’s than in most previous years possibly due to the cooler waters. The team did however manage to deploy all the tags they had on hand. A total of 9 mako and 3 blue sharks were tagged, three were among the largest animals tagged to date. One blue sharks that was 250cm fork length (FL) was double tagged with a SPOT /PAT pair. One 275 cm FL mako shark was too large to bring on board and was tagged over the side with a PAT tag. A second mako shark that was 223 cm FL was brought on board and tagged with a SPOT/PAT pair. The SPOT, PAT pairs will provide both high quality location data and information on vertical habitat use. So far six of the seven SPOT tags are transmitting as hoped and no PAT tags have reported prematurely. The sharks are all currently in the Southern California Bight and interestingly, close to two sharks tagged last year that returned to the Bight