The Search for Megalops – Report #1 – March, 2015
The Sound School Regional Vocational Aquaculture Center
Blue Crab Research in Long Island Sound 2015
You Do Not Need to Be a Scientist to Report
· Introduction to the 2015 Blue Crab Season
- Atlantic Seaboard Blue Crab Indices Decline
Follow Megalops reports on Resources, CT Fish Talk™, Saltwater Reports and The Blue Crab Blogspot™.
Introduction to the 2015 Blue Crab Season
For many Connecticut blue crabbers last year’s season was often disappointing; numerous checks at the Baldwin Bridge DEEP fishing pier drew mostly negative comments such as, “What happened?” or “Where are they?” were frequently heard. It is hard to explain how the Connecticut River Blue Crab Fishery declined so quickly when area newscasters, The Hartford Courant (June) and Fox TV News came to the Sound School last July for a Blue Crab report. Sound School’s Chris Jennings and Ceondice Johnson, both students, and Steve Joseph worked hard to catch a few blue crabs to show for the camera. In July, Steve Joseph, a teacher here was able to catch one blue crab just a few minutes before the cameraman and Fox anchor reporter, Katie Corrado, arrived to show for the camera. The Fox News’ broadcast on JULY 14, 2014 showed catches at the DEEP Marine Headquarters and adjacent to the fishing boardwalk which I feel saved the report. Earlier in the spring, The Hartford Courant reporter, Greg HLadky, covered the rise in Connecticut’s blue crab population since 1998 in a June, 2014 article titled, “Could Global Warming Turn the Sound into Blue Crab Haven?” The 2014 blue crab season would however for most crabbers fall far shorter than previous years had. West of the Connecticut River, 2014 catches were non-existent or very slow all year. CT River catches I observed at the Essex Town Dock never broke 8 crabs/hour ----with four lines this was the blue crabbing I experienced in the 1960s growing up in Madison, CT, not the recent past with catches of 65 to 100 crabs per hour (Megalops #3, July 23, 2013). Those high catches seem so distant now, so are the very warm “calm” winters we had leading up to these high catch figures.
Some blue crabbers last year did well however, knowing where habitat refugia occurs; it is these habitats (salt pond or deep coves) that hold the last good populations – and crabbing was good and at times very good. In times of declining habitat quality crabs can become compressed into those areas. In many respects, last year resembled for me blue crabbing in the 1960s (Great Blue Crab Years and Then None, September 8, 2010 – reissued Blue Crabs and Climate Change, August 2, 2012 – Northeast Crabbing Resources – Blue Crab Forum™); good catches in some years and very few in others.
2014 Blue Crab Season
Habitat compression can skew the season, if you knew where better than average quality habitat was (and the reason some veteran crabbers told me you need to find the crabs; they won’t find you!) chances are you did great. If you relied on previous habitat quality locations from a few years ago your chances are pretty good last year was poorer. That happened in the Saugatuck River where once excellent spots for blue crabbing in 2011 suddenly became leaf filled and sulfide smelling areas (IMEP #27, September 30, 2014, Blue Crab Forum™ Fishing, Eeling and Oystering thread) and crabs left. The 2011 Megalops reports give an account of what happened when heavy July rains hit western Connecticut for days, then September 7th Storm Lee, and before that Hurricane Irene in 2011. After these three rain events some productive blue crab habitats in western Connecticut were gone- not gone as recognizable areas but gone; in terms of habitat quality, changes can happen that fast (the late season, 2011 Megalops reports mention this change (Blue Crab Forum™ Northeast Crabbing Resources, 2011 reports compiled).
Thanks to some reports from Black Sea Bass fishers our CT Megalops Set (Long Island Sound) occurred late again (Megalops #4, October 9, 2014) for the third year in a row. Worst still the reports of sponge crabs, crabs with an egg apron or mass dropped suddenly. That does not give a positive outcome for this year, only time will tell. The only female sponge crabs were observed east of the Connecticut River last year (2014).
In 2010 I made a presentation before the Long Island Sound Study that we were using entering the season 1.7 degrees below average, but a hot summer soon erased that decline, yet a cold spring can delay the Megalops Set, an early appearance in March-April had incredible impacts on the Blue Crab season in 2010. That happened again after very mild winters and a warm spring in 2012, which had legal size blue crabs in the lower Connecticut River being observed on April 17th (Megalops #2, April 23, 2012) and Long Island Sound temperatures of 46° on St. Patrick’s Day. This year Long Island Sound temperatures were around 34°, twelve degrees less.
Since the NAO* turned negative since 2010, our winters have become colder and snow filled. I expect a much cooler than average spring (considering it snowed here a week ago) and we now have a giant ice cube up north ready to release cold melting spring water into Connecticut for weeks.
*For those interested in the climate feature NAO, the climate website for the State of North Carolina, I feel has the best description; it is found on http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml
2015 Blue Crab Season
How does this season look? Slow, I am afraid, the constant pounding of estuarine bottoms from a series of Nor’easters can’t be good for small crabs, winter flounder and hard shell clams (even lobsters) may have much better habitat quality, but not so for blue crabs. Several crabbers have already asked and I was not that optimistic.
I think this year’s blue crab season will be a challenge for most blue crabbers here in CT.
All blue crab habitat observations are important. Thank you for your interest and observations as the Search for Megalops turns five years old.
Tim Visel, The Sound School
Atlantic Seaboard Blue Crab Production Indices Decline
During the past few weeks, some of the Atlantic Seaboard population catch statistics have come in- all show declines (see Blue Crab Blogspot™). Some of the indices are also in and many mention a decline in the smallest sizes- the 1 to 2-inch range. I have noticed this here in Connecticut as well. This year classes (Megalops set) appear to be missing or not nearly as abundant as 2010 or 2011 and last year’s cold winter certainly had an impact upon the Connecticut River fishery (Megalops #3, August 20, 2014). Although crabbers tend to notice the larger crabs, the most important indicator for the future is what’s “coming up.” The Megalops reports’ observations in 2011 and 2012 include numbers of small or sublegal crabs surpassing those of legal 5-inch point-to-point sizes. In other words, there were more sublegal crabs from legal (based upon observations). Chances are that if you caught a crab last year, it was large; very few small crabs were observed last year, except in shallow salt ponds or coves. I stopped in at the usual places last year and observed only 3 small 2-inch crabs where as in 2011 I observed at times dozens if not hundreds of them in the same area.
Range Changes – Possible Retreat From Northern Areas?
Going back to Bigelow and Schroeder (1955) they wrote that Cape Cod tended to be the dividing line between the crab indices with the blue crab “southern” species and those more typically found in the Gulf of Maine rock and Jonah “northern” species. While that appears to be the physical boundary, the Gulf Stream has much to do with some southern species going far north as do our climate patterns. For hundreds of years fishers have noted the influence of warm waters moving north bringing “southern” fish along with them, even at times the blue crab (Megalops). Cape Cod did more to steer away the Gulf Stream than divide the Atlantic Ocean into realms of species dominance – if the Gulf Stream hugged the coast of Maine it would get those tropical species each August as we do here in Connecticut. Two years ago, several seahorses were caught in blue crab traps in Clinton Harbor – everyone knew they weren’t “native”. I used to see pilot fish circling our mooring chains off Webster Point in Madison, Connecticut in the 1970s usually in late August when water temperatures were the highest. I never used to think about what happened in the fall when water temperatures dropped, they most likely perished.
This Gulf Stream feature does complicate the more northern blue crab fisheries as well and the question could be asked if our Megalops sets are reinforced by transport up here by winds and currents. The year that measures the point of increase for New England is 1998. The index for all three states (CT, RI, and MA) shows improvement in blue crab indices all at once in the same year (1998). Blue crabs have made it into Great Bay, New Hampshire in 2010, although not in great quantities and the southern portion of Maine in 2012.
Now the indices to our south have turned negative and we don’t know yet when this will bottom out, no one is really certain. Expect these northern blue crab populations to gradually decline as cold water reduces the population range. I have mentioned the NAO, the North Atlantic Oscillation several times before (if you want to visit a state that has done an excellent job talking about this, it’s North Carolina) population cycles that has to be considered, predator-prey relationships have a part for certain, but habitat capacity and habitat quality most likely have the largest roles and the areas we know the least amount.
Rhode Island has also noticed an increase of blue crabs (especially in 2010) and is now looking at Megalops settlement in coastal salt ponds: the Massachusetts inshore seine survey showing the same for the Cape and Islands – recent increases in the smallest blue crabs. One of the first questions at the beginning of the Megalops newsletters was could the Chesapeake Bay Megalops make it into Long Island Sound and under the correct conditions add to the blue crab fishery here. Perhaps the Rhode Island Megalops study (to be released shortly) may answer that during high reproductive periods southern Megalops may hitch a ride to northern waters; I believe they do.
Fishers and a Long Term View
The biology also has a factor in recent catches and blue crab fisheries management. Blue crabs have relatively short life cycles; they have enormous reproductive capacity and have the ability to respond quickly to increases in habitat quality/quantity. The boom and then bust of crab catches [The same could be said for the northern Gulf of Maine Shrimp industry]. When habitat quality is favorable, enormous reproductive potential is ready when habitat quantity declines reproductive capacity is wasted, and within parameters extinction events, an almost total habitat failure can happen (both at once). The best example to dates I have found is Bay Scallop Fishery (1910 to 1915) in Narragansett Bay, Rhode Island. As habitat conditions failed for bay scallops during the Great Heat (1880-1920), bay scallops practically disappeared from a huge deep-water bay scallop fishery there of the 1870s.
By 1910 finding a bay scallop was rare, but by 1924 after two bitter cold winters, bay scallops were back in Rhode Island, as they, with a very short life span (30 months) quickly became a dominant shellfish species again. At first Rhode Island fishery managers were shocked, they just didn’t have any reason for the sudden bay scallop surge, into the hundreds of thousands of bushels (1924); eventually it was summarized due to fishery management efforts, closed fisheries. But when you examine the management efforts then there was nothing left to manage, the bay scallop had gone and with it a way of life along Narragansett Bay. But in the 1920s Bay scallops returned (not as much as the 1870s) and also the coldest winters in New England in 50 years – fishery managers commented that despite the brutal cold winters bay scallops returned not in spite of them, but because of them – they like cold and energy. Bay scallops have again “returned” to the Cape Cod and Islands. Winters have been colder with storms and bay scallop catches have generally improved in northern areas.
Blue Crabs it seems do not “like” the same conditions; hurricanes and tropical storm rains can wash Megalops from coves and bays and then flood bay bottoms with built up organic matter from land. This appears to be happening in the Saugatuck River from July 2011 on into Irene and then Sandy (Megalops Report #12, August 2, 2011). This organic matter is under the proper conditions can become sulfide rich and toxic. Bay scallops and blue crabs can swim so they can both move in areas of high density to low – and in respect to bay scallops act somewhat like marine locusts – consuming enormous quantities of green algae and when food supplies diminish moving into a new cove. The historical fisheries literature is filled with references that talk about sudden appearances of bay scallops and how some coves were filled one day and empty the next. The habitat capacity, perhaps, ran out and they moved on to new areas (this led to some bay scallop jurisdiction conflicts on Cape Cod in the 1950s). This also explains why blue crabs when faced with toxic sulfide levels simply leave the water. Habitat capacity and quality are huge factors but need to be assessed over time. One New England example is the hard or round Quahog clam. The Quahog clam is a shellfish that can live to be 80 years (or perhaps more). Although Quahogs usually spawn every year, the big sets or jumps in habitat capacity occur after cold periods with hurricanes. Here coastal energy (read marine soil cultivation) is applied at great depths from waves- turning sulfide rich organic soils over – releasing the sulfides and organic acids into colder well oxygenated seawater that is now basic, slightly alkaline. This is the marine soil that has the highest habitat capacity – for shellfish sets, loose sand, free of sulfuric acid and mixed with estuarine shell; these are the bottoms that produce the “great sets” as they did in Narragansett Bay after the 1938 hurricane and the hurricane seasons of 1954-55. This was a habitat reversal of huge scale, measured by increased Quahog catches; long dormant bottoms acidic and much filled were re-cultivated and rinsed of acids. The sets two to three years after these hurricanes (soil stabilizes) and the Quahog sets were huge reflected years later in dramatic increases in Quahog harvests. This was (1950s, 1960s) in a negative NAO period – colder water favored the quahogs. Blue crabs, however, declined during this period. Quahogs were in shallow water coves and bays as well as the deep waters and when it became warmer an Eelgrass/Sapropel habitat soon reduced habitat quality and capacity quahog sets declined, that is why Cape Cod Quahogers despised eelgrass in the 1960s and 1970s; they watched as it “took over” and changed the habitat quality for hard shell clams. The marine soils now in high heat became acidic, killing clam larvae and then suffocating the adults. Quahog fishers at the time watched as clam habitats were overrun by eelgrass but there was really nothing they could do. Waters warmed in the 1970s, 1980s and 1990s and bay scallops became scarce. However, blue crab prevalence now increased
This was also a blue crab “cycle” a century ago. The Great Heat 1880-1920 brought a similar habitat reversal; acidic bottoms and eelgrass trapping organic matter in high heat and Sapropel destroyed the deep water bay scallop habitats of Narragansett Bay, when the habitat capacity – quality declined so did sets of bay scallops, but blue crabs greatly increased.
The eelgrass Sapropel habitat type extends its coverage during periods of high heat and low energy, cold and energy destroys this habitat and with it eelgrass meadows. The same period saw however a dramatic increase in blue crabs (1880-1920) on as the climate warmed and storm intensity declined – eelgrass flourished and Sapropel deposits grew deep. Blue crabs as well in these habitats seemed to reverse conditions then and lobster populations fell sharply during the hottest heat waves of the 1890s. You can only see these influences of climate if you look at the long-term historic fishery statistics. A habitat history, if you will, combines temperature and energy as dominant factors, not pollution or catches. In fact, catches first appear to be the best indicator of previous habitat quality changes, to energy and temperature, which to my knowledge still remains out of our control, or just natural.
In other words, the ups and downs of a fishery catches largely are beyond our control and there are many examples in the fisheries’ literature; in the 1870s striped bass here were small – 8 pounds and that was a newsworthy catch, but The Great heat (1890s) the Cape and Islands had fishing clubs that specialized fishing for these huge cow stripers. In times of great heat for Striped Bass, they can reach enormous sizes and in times of great cold, they do not.
It is still too early to reflect upon the declines of the more southern blue crab catches for us here in Connecticut, but for the first time I see signs of a large habitat reversal here under way (striped bass kill Black Hall River). Other examples exist, but it’s still too early to show in the catch statistics. The Cape Cod Quahog fishers of the 1970s for example declared war on eelgrass, but it was a habitat war they could not win; it was just getting warmer; now it seems to be getting colder. We might not like the outcome of this one either, an event that could take decades to play out; we may not like the score but still forced to watch the game.
We should know in a year or so if Quahogs set heavy in Long Island Sound deep waters again, monitoring Quahogs sets in Narragansett Bay (if the cold continues) are also important. Another historical indicator for Long island is Great South Bay (NY). After the 1938 and 1954-55 hurricanes, the Quahog sets in Great South Bay were huge, but largely failed in the heat when there were few storms (1974-2004).
Sulfide Kills Possible to Hibernating Blue Crabs
One habitat factor that is still understood is the cycle of Sapropel and its ability to produce sulfide “waters.” The largest component of Sapropel in our area is trapped terrestrial leaves.
Some of our coves (and rivers) have obtained leaves from a newly removed forest canopy – in some places several feet. This is the Sapropel I wrote about last year.
In shallow areas with eelgrass, this accumulation at first enhances blue crab habitat quality, but when it deepens it “putrefies” and sulfur reducing bacteria consume it creating toxic amounts of sulfide releasing it into the water column or when disturbed by currents or ice. In other words, at the end of its habitat succession the eelgrass/organic meadows became deadly and a source of toxic sulfides.
I am getting a few reports about dead adult blue crabs; although many reference the cold, I do suspect sulfide toxicity. One of the rivers that has been impacted by leaves is the Saugatuck, so that one is key to watch, but many estuaries that receive raw storm water or street water without recharge basins I believe also obtained huge amounts of organic matter after Irene and Sandy. Spring runoff also carries large quantities of organic matter. It could take years for these organic deposits to “recycle.”
Our trees are back and with a leaf-burning ban in the 1970s, larger amounts of organic oatmeal (leaves) are entering watercourses. The oatmeal first described and known to me by the Quahog fishers of Lewis Bay on Cape Cod (1981) was ground up leaves and dead grass swept into streets and ground up into a pulpy brown “oatmeal” slurry that in heavy rains is washed into bays and coves. I think everyone has seen this in the fall by road curbs and sometimes filling street basins. Towns try to keep them cleaned as they themselves become putrefied and contribute to sulfide levels. If the basins are not cleaned they start composting themselves. During The Great Heat, 1880-1920, manure from dairy farms was the source of putrefying organic matter – most of the trees were then cut down for pastures but today it is the renewed forest canopy and paved water courses that deliver organic matter (leaves) to estuarine habitats. Organic matter can overwhelm habitats changing them. This happened in Europe 1865 to 1915 approximately the same time as our Great Heat- in fact, the climate period we experienced then is remarkably similar to that of the European “Great Stink” a few decades before our last warm period. Here Europe’s rivers filled with organic matter, manure and sewage, putrefied at times, forcing people to flee from the noxious fumes.
It was two biologists, Marsson and Kolkwitz, who developed the pollution index of organic matter and the damage it can cause to environments called The Saprobien System (Sapropel) (See Megalops Reports #8, September 4, 2014, #2, February 2014 and #4, October 7, 2014). Dick Harris of EarthWatch™ has studied the Saugatuck River for decades and is one of the first researchers to ring the alarm bell for the damage from organic matter, primarily leaves.
The cycle for Sapropel and eelgrass over it has in my opinion helped blue crabs, but in the end, this can cause sulfide kills in high heat. Rhode Island recently had one of these warm water sulfide kills in Greenwich Cove. It just got too hot.
Such events often mark transitions between the cycles, the end of one and beginning of another. Some of the species that seem to be abundant in the transition years are kingfish and weak fish. The other in (heat) that signals massive habitat quality change is the blue crab, and in cold the bay scallop. Both blue crabs and bay scallops appear in the fisheries history to quickly fill habitat voids – opposite each other in relative abundance.
The 2015 blue crab season for Connecticut following two years of a delayed Megalops set could be an indicator for blue crab populations that increase and decrease in cycles and recorded catches. That is why all observations are important. In a few weeks, the Chesapeake Bay winter dredge survey will be released providing key information on blue crab survival of a very long winter.
Email your blue crab reports to: email@example.com. All blue crab observations are valuable as we learn more about our blue crab population. Questions? Send me an email.
The Search for Megalops is part of a Project Shellfish/Finfish Student/Citizen Monitoring Effort supported by a 2005 grant to The Sound School from the National Fish and Wildlife Foundation grant #2005-0191-001. Program reports are available upon request.
For more information about New Haven Environmental Monitoring Initiative or for reports please contact Susan Weber, Sound School Adult Education and Outreach Program Coordinator at firstname.lastname@example.org.
The Sound School is Regional High School Agriculture Science and Technology Center enrolling students from 23 participating Connecticut communities.