CTFishTalk.com: Blue Crab Report #10 - July 20, 2011 - Connecticut Saltwater Reports ( CT Saltwater Reports ) - A Community Built for Connecticut Fisherman.

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The Blue Crab Year -
The Search for Megalops – July 20th 2011- Report #10
You do not need to be a scientist to report!

Reports 1 to 9 are available – email Tim Visel at tim.visel@new-haven.k12.ct.us

• Niantic Bay Report – No crabs, isolated population in Jordan Cove; Alewife Cove, no report; eastern areas, no reports.
• Population mix changes in west as blue crabs shed into legal sizes
• Yellow face crabs in New Haven Harbor
• Small crabs confirmed off Fairfield, Bridgeport, Stratford area
• Another western Megalops hatch should enter fishery September 1; more hatches possible late summer to September
• Crabbers’ comments: What is happening?

Thank you for all the crab catch/habitat observations – they continue to be extremely helpful.

My visit to Niantic Bay last weekend was somewhat disappointing. I had expected to see blue crabs. I did see some blue crabbers however but no crabs. A few times I inquired about ‘luck’ but was answered by none. A couple of people asked what happened, expecting to find a bountiful supply of crabs like last year, but now nothing. I didn’t get into a long conversation, but you could tell disappointment was in the air. One of the boaters I spoke with was also dumbfounded last year declaring ‘you didn’t need bait here to go crabbing; last year people just walked the docks and netted them off the poles,’ but this year, nothing, and if the crabs weren’t here, where were they? Questions I could not answer and because so many eastern and central crabbers have requested this information, I thought I would summarize what I believe is taking place.

First of all, after reading some of the western reports these past few weeks, I guess I started blue crabbing at the wrong time, the 1960s. Blue crabs were scarce then and a few of my recent conversations have confirmed my suspicions – we now have significant habitat changes in Long Island Sound. The crabbers I talk with mostly in New Haven – Old Saybrook area, agree and want to know about suitable areas for small blue crabs – they want to know why, this year is so different from last year, and most importantly, “Where are all the small crabs?” and “What happened to all those adults? We surely didn’t catch them all?” Good questions. Last summer I most likely would have attempted to respond to both but this July, I’m not so certain. It is apparent from last year’s wonderful catches that eastern habitat areas can support immense blue crab populations (at one time last July catch rates at the Essex Town Dock exceeded 90 keepers/hour) of many sizes but cannot sustain them. Most of the crab resource in the east last April was gone, where I do not know. I have an idea but it’s not good for eastern crabbers.

The western sections tell a completely different story here. Crabbers found in April a sizeable already legal size population with a huge 3 to 4 inch population; an emerging 1 to 2 inch population and now another dime to nickel size crop of small crabs on the way. I didn’t have any eastern blue crab reports like that. Not a one. In fact, the absence of small crabs in the east has been the concern most often expressed.

Where are the small crabs from last year? Again I’m uncertain. The east is missing almost all of its crabs. What I did obtain was several reports detailing a small male population, mostly over wintered in deep creeks or dredged marina channels. Several crabbers expressed these concerns from the CT River area.

Crabs were few and no small ones observed --what happened to them? I believe they could not withstand the fresh water runoff or predation from high salinity predators. In other words, they didn’t make it; several million crabs were gone, and it’s not just last year’s crabs that were missing, but the previous years’ as well. Most researchers agree that blue crabs live between 5 and 8 years, so missing from the population matrix was surviving/returning crabs from 2007, 2008, 2010 (2009 was a poor year in the east) while 2008 was also good; it did not match 2010.

As more and more central and eastern crabbers return to the shore with great anticipation, based on last year’s experiences, conversations all point to all too familiar question, what has happened and realizing that small crabs shed into large crabs, the absence of so many of them. The Run. The ratio of caught crabs, all sizes to the number of legal crabs is a way to look at this. Many reports have them and assists in understanding the differences.

Legal to sub legal – run

Early eastern run- when crabs were caught- the run- was nearly 1 to 1. In other words, almost every crab eastern caught was of legal size.

The western run tells the difference. It started at 3 to 1 than 4 to 1, and now is 5 to 1. In other words the west started with a sizeable sublegal population that has now grown in size; for every legal crab returned in the west, 4 or more crabs are released. With the 1.5” to 2 inch size, now growing into a size that can be observed (trapped or netted). The Run may go to 5 to 1; for every legal crab returned 5 sub legal are returned. Several western crabbers report a run closing to that amount, but should quickly change as crabs shed into legal size.

Catch counts:

Again large differences

East – April May June – catches (counts) ranged from none to 12 most between 4 to 12 and only recently into the teens and beyond (most after July 1st.)

West – April to June – catch counts were already in the 20s and now in the 30s. With so many sublegal crabs on the way I expect counts to increase some 40s to 50s already in with hundreds of sub legal crabs returned and news of another a new potential crop on the way. I expect counts to increase.

Length of trip – many crabbers have put in hours fished. It’s a good measure. I use it too. Went for four hours, caught 20 crabs, etc. so information of catch/hour is helpful especially comparisons between western and eastern areas.

Again, here large differences: some eastern crabs reported 4 to 6 hour trips and producing only a few crabs while western spring reports were almost 4 to 5 times the trip/catches of those to the east.

Catch per effort – many reports refer to the number of hand lines or baited traps used. This is the most difficult to assess, many reports vary as to effort. Some use 3 or 4 traps, other lines. Some use a mixture of lines and traps. In a four minute period last July, my son Willard caught 17 crabs from 4 hand lines and four traps at the Essex Town Dock, but I’m assuming from the length of trip and differences in catches, the return/unit effort was also very different. For a two week period crabbers in Clinton Harbor averaged less than 1 crab/trap/hour, sometimes much less than that.

Habitat observations – Again they have been very helpful; the east was concentrated early in the deeper dredged channels while the west, coves, marsh banks and creeks. The west appears to be more distributed habitat while the east concentrates in tidal creeks. Salt ponds seem critical but most of the salt ponds in the east were filled in or blocked by causeways. The western areas the sub tidal areas seem to be much larger and healthier. The Fairfield area in particular has been identified many times as significant source of small crabs. The bottom line is we just don’t’ know a lot about the ecology and habitat conditions. That is why we need to locate areas that support Megalops.

All these eggs are produced somewhere and in large enough quantities to represent our current western population. Some questions have been raised about “female black aprons”, a sign of egg maturation before extrusion- these are not true sponge crabs; it is the external orange shaded egg mass, the so called sponge. But every fertile female crab can produce 3 such sponges between June and September and each can contain 2 to 8 million eggs. The sponge changes color from an orange/yellow to a dark brown or black just before the egg capsule bursts- water temp 65° or higher. They then drift subject to currents. The first stage is called Zoeae, not recognizable as a blue crab. After about a month, it turns into a Megalops which takes about a month, molting into what looks like a crab (the Megalops stage looks like a shrimp or lobster). In about 3 more months, these crabs are still small about the size of a nickel (or 4 months total). Therefore the reports of dime to nickel size crabs are the result of last season’s Megalops. This year’s Megalops should show about 60 days after 65° water temp or spawning. If some western areas reached 65° in June and sponge crabs released Zoeae we should see “Connecticut” Megalops in early August. Three to four waves of Megalops set are possible and is one of the study research areas. With extended warm temperatures sponge crabs may have viable Zoeae hatches into September. One of the unique features of Megalops is that they also can hibernate in cooler temps for about 3 months.

The Megalops is the most interesting and may I say, the most uncertain segment of the blue crab life cycle.

A September Zoeae can become a Megalops by December, and remain dormant in locations (which we do not understand) for about 3 months. If the water warms in time, Megalops can survive the winter and start to grow and begin molting into small crabs in early spring. In June, July, they would be about the size of a nickel the size now reported of the Fairfield to Bridgeport region. These crabs most likely represent the last viable hatch from the fantastic 2010 crab year. They are next year’s crabs and they should reach 3 to 4 inches by September, hatches beyond now should be 1.5 to 2” by September, the late hatch should produce that overwintering Megalops. That is what we hope to locate and measure. That would answer the question of Connecticut female crabs produce Megalops that make it; (over winter) another theory and one that I may need to abandon is that Connecticut Megalops came up upon the Gulf stream currents, that our Megalops was excess Chesapeake Bay Megalops drift theory. But what is now happening in Connecticut appears to be that our crabs can over winter, our crabs do sponge out, and that incredible densities of Megalops exist.

What crabbers have reported – rephrased as needed/combined reports from dock visits also.

1. The prevailing winds southerly blow the eggs (Zoeae then Megalops stages) back along Connecticut’s coast increasing the hatches. It’s now fairly common to see such hatches, while fishing all summer long in the water.

2. Crabs move and dispersed by strong tides, moon tides, and it’s not one wave of crabs but many; smaller waves did occur in May and June, but only reached Branford. The July “wave” made it all the way to the Connecticut River; it’s like a switch one day none the next day loaded. (Perhaps east and west as well).

3. We should return all females, (it’s not like before) west of Milford they make it (over winter) now, breeders for next year. Years ago they didn’t (egg out) now they do (survive) East of Milford sponge crabs appear to be scarce.

4. Crabs move along the coast do so for the purpose of getting into the marshes to shed. If you get a lot of crabs at the mouth of creeks or rivers, and then follow them up to the upper reaches, they do not stay until they shed, they march up the river in the spring, in the fall they march out.

5. Small crabs earlier last year, warmer temp and tides dispersed in (them) in June; that was what the eastern crabbers had, this is why last July they had so many shorts, we have that now every year in the west (Note: several current western crabbers report 80% of the crabs are still sublegal, while in the east 80% are now legal.)

6. Habitat conditions much different in the west/east; water is ocean cooled too many large rivers (Connecticut, Thames) too much fresh water.

7. Most of the small crabs come from the Stratford/Bridgeport /Fairfield Creek areas. The creeks loaded with shorts, stripers feed on them at night- ebb tides.

And it’s not over- reports now include a huge set of dime size crabs along the Milford shoreline and moving with the tides. The predation upon them must be intense, in fact a recent Sound School graduate reported that he caught fluke off West Haven beaches that were loaded with the small crabs, and the stomachs were just packed with small blue crabs. Blue fish caught recently at Saybrook Point had small blue crabs in the gut cavity.

As for the yellow color, Steve Joseph one of the Sound School teachers here brought one to show me last week. It had a beautiful band of yellow underneath, but according to some veteran crabbers, it’s a hard shell crab soon to shed. The crab that Steve showed me did have a rock hard shell and looked like those observed in the Oyster River, Old Saybrook a few days ago.

I guess we wait now to see these small crabs make it east, no reports from Niantic east. Perhaps in the next few days with central CT catches modes to good, a sign of small crabs would be welcome.

The western reports all include good to excellent catches with a large percentage of small undersized crabs, but that May/June population of 3 to 4” crabs will be soon shedding into legal size within the next two weeks, the caught/keep ratio (run) should change. Western crabbers will experience a surge in keepers around the first of August. I think they are correct; it should be quite a surge into a size that can be observed (trapped or netted).

Thank you again for all the crab reports/comments.

Observations this year will help guide the survey methods for next year.

Every observation is important you do not need to be a scientist to participate!

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.

All observations are valuable; please email them to me at tim.visel@new-haven.k12.ct.us.

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 susan.weber@new-haven.k12.ct.us