DIVE DRY WITH DR. BILL #669: THIS REALLY "BUGS" ME
Those of you who read my column regularly are undoubtedly aware that during the warmer months I often take my dips in the dive park at night to avoid the crowds. With the unusually warm waters the past two years, I've been able to extend my night dives into late fall and even early winter. Most of them were in my thin 3/2mm wetsuit although I recently switched to my new 5mm one despite the fact the minimum temperature on one of my last dives to 100 feet was 67 F!
I don't dive at night only to escape the crowds. I do so because there is lots of action at night as predators such as the big "bully" bass, morays and sharks come out at night to feed. They are joined by a very popular invertebrate known to many as a "bug." Yep, I'm referring to the California spiny lobster (Panulirus interruptus). Of course many other divers who descend at night this time of year do so to act as predators on them.
Way back in 1975 I stopped taking lobster. I have no problem with those who do take them legally and in moderation. In fact, if one of my buddies offers me a bite of the bug, I'll indulge. However, despite the Dept. of Fish & Wildlife's assurances, I think our spiny lobster have suffered as a result of over harvesting.
The dive park has become an official marine protected area, so divers aren't allowed to take bugs (or anything else) there. However, hoop netters legally ring the boundary line of the park and take the lobster who venture beyond its boundaries in the nocturnal search for munches. This is perfectly within the fish and game regulations, but I firmly believe it has had a negative impact on the bug population in the park. It also reflects poor marine reserve design based on scientific principles. To protect the species within a reserve, it needs to be large enough to encompass the wanderings of the adults.
When I dive at night, I often see dozens of lobster crawling around on the bottom... at least when the invasive Sargassum seaweed hasn't become too thick. What I don't see is a reasonable number of legal sized bugs and only very rarely one that would remind me of the days in the 60s and early 70s when I'd hunt for them myself. Although numerous, most are undersized indicating that the age structure of the population is skewed. The "big" ones (by today's standards) are missing. The big ones by yesterday's standards are practically non-existent.
I said I have little argument with those who take legally. However, I do have a big concern about those who misinterpret (or simply ignore) the law about limits. Many think it is okay to take seven of them on each dive since that is the stated limit. However, that limit applies to ALL the lobster a diver has in possession at one time. You have to count the (sometimes) dozens of them in your freezer as well. Fortunately you don't have to count the ones in your stomach even though technically they are in your possession!
Conditions over the past 20 months have also affected the lobster population here. The unusually warm water associated with The Blob and el Niño has affected food sources for bugs. A major impact is the death of many of our sea urchins due to elevated temperature and disease. Bugs love to munch on these spiny echinoderms both for their tasty gonads, and for the exoskeleton-building calcium carbonate in their tests. With so few urchins surviving today, an important food item has been removed from their menus.
Yes, lobster are scavengers and will eat almost anything. So what are they turning to as a substitute for the urchins? They will eat their discarded exoskeletons for the calcium, but there's little "meat" on them. Mussels and other bivalves are another source, and you can often see lobster "bites" on their shells. One surprising observation I've made over the last 20 months is that they will chow down on a relative of the sea urchin, the sea cucumber! Cukes have a lot more meat to them, and they also contain calcium carbonate. However, during the current warm water period, I've also noticed fewer sea cucumbers. Water temperature may be affecting them too, and there are signs of a potential disease in the population.
So, yes... it "bugs" me that I see so few lobster of the size range I remember from the good old days. And, no... I don't think my aging brain has created a fish tale out of the ones we used to catch. Healthy bug populations require a range of age groups. Successful reproduction requires both numbers and size since the bigger bugs produce more. Yes, size does matter! And don't blame the commercial guys... their traps have excluders that limit the size of the lobster they take. I have wondered if the bugs may have turned to munching sea cucumbers for another reason. Many Asian cultures believe cukes enhance a male's reproductive ability. Perhaps the bugs are trying to enhance theirs to make up for the lack of size.
© 2016 Dr. Bill Bushing. For the entire archived set of over 650 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Everyone loves a little "tail" and bug munching on sea urchin; getting their calcium from a lobster molt and a sea cucumber.
Those of you who read my column regularly are undoubtedly aware that during the warmer months I often take my dips in the dive park at night to avoid the crowds. With the unusually warm waters the past two years, I've been able to extend my night dives into late fall and even early winter. Most of them were in my thin 3/2mm wetsuit although I recently switched to my new 5mm one despite the fact the minimum temperature on one of my last dives to 100 feet was 67 F!
I don't dive at night only to escape the crowds. I do so because there is lots of action at night as predators such as the big "bully" bass, morays and sharks come out at night to feed. They are joined by a very popular invertebrate known to many as a "bug." Yep, I'm referring to the California spiny lobster (Panulirus interruptus). Of course many other divers who descend at night this time of year do so to act as predators on them.
Way back in 1975 I stopped taking lobster. I have no problem with those who do take them legally and in moderation. In fact, if one of my buddies offers me a bite of the bug, I'll indulge. However, despite the Dept. of Fish & Wildlife's assurances, I think our spiny lobster have suffered as a result of over harvesting.
The dive park has become an official marine protected area, so divers aren't allowed to take bugs (or anything else) there. However, hoop netters legally ring the boundary line of the park and take the lobster who venture beyond its boundaries in the nocturnal search for munches. This is perfectly within the fish and game regulations, but I firmly believe it has had a negative impact on the bug population in the park. It also reflects poor marine reserve design based on scientific principles. To protect the species within a reserve, it needs to be large enough to encompass the wanderings of the adults.
When I dive at night, I often see dozens of lobster crawling around on the bottom... at least when the invasive Sargassum seaweed hasn't become too thick. What I don't see is a reasonable number of legal sized bugs and only very rarely one that would remind me of the days in the 60s and early 70s when I'd hunt for them myself. Although numerous, most are undersized indicating that the age structure of the population is skewed. The "big" ones (by today's standards) are missing. The big ones by yesterday's standards are practically non-existent.
I said I have little argument with those who take legally. However, I do have a big concern about those who misinterpret (or simply ignore) the law about limits. Many think it is okay to take seven of them on each dive since that is the stated limit. However, that limit applies to ALL the lobster a diver has in possession at one time. You have to count the (sometimes) dozens of them in your freezer as well. Fortunately you don't have to count the ones in your stomach even though technically they are in your possession!
Conditions over the past 20 months have also affected the lobster population here. The unusually warm water associated with The Blob and el Niño has affected food sources for bugs. A major impact is the death of many of our sea urchins due to elevated temperature and disease. Bugs love to munch on these spiny echinoderms both for their tasty gonads, and for the exoskeleton-building calcium carbonate in their tests. With so few urchins surviving today, an important food item has been removed from their menus.
Yes, lobster are scavengers and will eat almost anything. So what are they turning to as a substitute for the urchins? They will eat their discarded exoskeletons for the calcium, but there's little "meat" on them. Mussels and other bivalves are another source, and you can often see lobster "bites" on their shells. One surprising observation I've made over the last 20 months is that they will chow down on a relative of the sea urchin, the sea cucumber! Cukes have a lot more meat to them, and they also contain calcium carbonate. However, during the current warm water period, I've also noticed fewer sea cucumbers. Water temperature may be affecting them too, and there are signs of a potential disease in the population.
So, yes... it "bugs" me that I see so few lobster of the size range I remember from the good old days. And, no... I don't think my aging brain has created a fish tale out of the ones we used to catch. Healthy bug populations require a range of age groups. Successful reproduction requires both numbers and size since the bigger bugs produce more. Yes, size does matter! And don't blame the commercial guys... their traps have excluders that limit the size of the lobster they take. I have wondered if the bugs may have turned to munching sea cucumbers for another reason. Many Asian cultures believe cukes enhance a male's reproductive ability. Perhaps the bugs are trying to enhance theirs to make up for the lack of size.
© 2016 Dr. Bill Bushing. For the entire archived set of over 650 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Everyone loves a little "tail" and bug munching on sea urchin; getting their calcium from a lobster molt and a sea cucumber.
