UNH Overview of Life History (From Factor, 1995, The Biology of the Lobster, Homarus americanus. Academic Press) Homarus Life Cycle Start Here Overview Overview of Life History and Reproduction From mating, to larvae, to adults Behavior of adults What can they sense? Migrations and homing Lobster Fishery How do we monitor the fishery? Overview of Life History (From Factor, 1995, The Biology of the Lobster, Homarus americanus. Academic Press) Homarus Life Cycle Start Here Molting and Mating /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/lobster molting.mov Typically molt once/year, older females every other year. Grow about 12% at each molt. Very vulnerable to predators following molt. This video courtesy of Diane Cowan Mating (~July-August) Females typically only mate after they molt. Male places a spermatophore in her seminal receptacle. spermatophores Spermatophores /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/lobster mating 1.mov Extrude eggs in fall and carry for ~ 9 months Interestingly, not all berried females are carrying fertilized eggs. Why not? Sampled > 2,000 female lobsters during 2008-9. Approximately 70% positive for sperm. Figure 7 large Not enough sperm to go around? And…maybe size matters: Female 17% larger /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/mating small male larger female small.mov Most surprising finding: more small females had mated than expected Data from submitted paper: Tracy Pugh, Jason Goldstein, Kari LaValli, Michael Clancy Note: legal=83 mmCL, 25mm=1inch Immature Mating or Global Warming? Second Most Interesting Finding: More than 90% of the 353 berried females (eggers) sampled also carried sperm. So they can fertilize two clutches of eggs with one mating (we have seen this on > 5 occasions). This might be one reason why many females only molt every other year. Berried females are very mobile. NH Seacoast 5-10 km from origin IOS Map > 10 km from origin Release site Do their movements influence egg development ? Yes. Movements influence thermal history temp comparison Maine: Cowan et al. NH estuary vs offshore Offshore changes more gradual: Warmer in winter, and does not warm up as fast in spring So, movements of females influence where and when eggs will hatch P6150161 Offshore: Most hatch July/August Inshore: Most hatch June/July Egg Drawing2 And then larvae drift around for 2-4 weeks before settling on bottom /Users/localadmin/Desktop/Sensory Talk Norway 2011/Secret Lives/Riverwoods 2007/Movies/lobster larvae.mov Do female movements influence the survival and settlement of larvae? Jason & Drifter.jpg Drifter (11-09)2.JPG Jason Goldstein Drifters IMG_2066.jpg larval4th Yes! Some go to George’s Bank Many to Mass GB Map And, what hatches in GB, stays in GB https://assetview.comtechmobile.com/portal/index.php Adult Behaviors and Senses Homarus Life Cycle Survival of the Fittest In past, large fish were major lobster predators. Thus, lobsters evolved to stay in shelters, forage only at night, etc. Now, in NH, major predators are other lobsters, skates, crabs. /Users/localadmin/Desktop/Senso ry Talk Norway 2011/Movies/skate eats soft legal lobster.mov Lobster Make Sounds Why do lobsters make sounds? Henninger, H.P. and W.H. Watson III. 2005. Mechanisms underlying the production of carapace vibrations and associated waterborne sounds in the American lobster, Homarus americanus. J. Exp. Biol. 208: 3421-3429. /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/lobsters making sounds.mov In part, to keep fish away /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/lobster and cod 9 9 .mov And some fish (striped bass) learn to stay away Data from: Dan Ward, Francoise Morison,Kyle Jenks, Elizabeth Morrissey and Win Watson. JEB 2011. Control: No lobster After experiencing sounds Lobsters can hear each other But I have no evidence that acoustic communication between lobsters plays a role in any behavior. Adult lobsters are very mobile Long distance movements. Some > 100 kms, up to 3-4 kms/hr Adult lobsters are very mobile Long distance movements. Some > 100 kms, up to 3-4 kms/hr going? Daily Movements 10-100 meters home range with track For Some: Survival Avoid low salinities….. nice large color great bay map copy Cardiac Assay Lobsters can detect a drop of ~ 3 ppt in salinity. Avoidance Assay Lobsters avoid salinities lower than 12 ppt. Can they sense changes in salinity? And females are less tolerant and respond more quickly! /Volumes/Win Backup/Talks/Seattle Fisheries Talk/Movies/cardiac response to water copy.avi Lobsters Behaviorally Thermoregulate Cold Hot In N.H. they prefer around 16oC in the summer. Crossin, G., S.H. Jury, and W.H. Watson III. (1998) Behavioral thermoregulation in the American lobster, Homarus americanus. J. exp. Biol. 201: 365-74. Thus, movements are strongly influenced by temperature and salinity and males and females respond a bit differently. Daily Movements What is a typical day for a lobster? /Volumes/Win Backup/Talks/Seattle Fisheries Talk/Movies/Tagging Process copy.avi They have homes and are very capable of homing behavior Even at night!!!!!!1 /Volumes/Win Backup/Talks/Seattle Fisheries Talk/Movies/meso homing.mov /Volumes/Win Backup/Talks/Seattle Fisheries Talk/Movies/sonar walking copy.avi More active in night, than day, but not strictly nocturnal* 2nd 7415 7-10 Day Day 0600-2000 20 M 2nd 7415 7-10 Night Night 2100-0500 20 M 2nd 7415 7-11 Day Day 0600-2000 20 M 2nd 7415 7-9-03 Night Night 2100-0500 20 M * Golet, W.J., D.A. Scopel, A.B. Cooper and W.H. Watson III. 2006. Daily patterns of locomotion expressed by American lobsters (Homarus americanus) in their natural habitat. J. Crust. Biol. 26(4) 610-620 One adaptation: see better at night! night response.png /Users/Win/Desktop/Win Work/Sensory Talk Norway 2012/Movies/Treadmill.mov Hour ERG amplitude Distance walked (cm) How do they find their way? CHUTE 3 copy IMG_2032 /Volumes/Win Backup/Talks/Seattle Fisheries Talk/Movies/walking lobster for talk short copy.avi Or maybe magnetic sense? /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/spiny q no sound copy.avi How do they find their way? CHUTE 3 copy IMG_2032 /Volumes/Win Backup/Talks/Seattle Fisheries Talk/Movies/walking lobster for talk short copy.avi Vision not necessary… All blindfolded91 Blindfolded N=72, Raleigh Test: p=0.045 S All sighted243 Normal N=200, Raleigh Test: p=0.007 S lobster in tube Our current hypothesis: Surge Or maybe magnetic sense? /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/spiny q no sound copy.avi Spiny Lobsters Use It Spiny lobsters orient toward their home reef when displaced. And, disrupting magnetic field disrupts orientation. helmholz /Users/localadmin/Desktop/My Documents/Talks/Homing and Navigation/walk copy.mov But:why is the lobster fishery so “stable” despite heavy exploitation? image001 And if they survive all of that: we get them LTV (Lobster Trap Video) Perhaps it is due, in part, to trap dynamics. * Jury, S.H., W.H. Howell, D.F. O’Grady and W.H. Watson III. 2001. Lobster trap video: In situ surveillance of the behavior of Homarus americanus in and around traps. Mar. Freshwater Res.: 52: 1125-32. ltv with lobster enterin small First, not all approaches lead to entries About 1 of every 5 animals that approach/enter! /Users/localadmin/Desktop/Sensory Talk Norway 2011/Movies/2) LTV Lobsters hesitate to enter.mov Second, lobsters in the trap limit catch Traps “saturate” fairly rapidly (hrs, not days). /Users/localadmin/Desktop/Norway/Norway Talk and Poster Stuff/Movies and images/LTV8_24_99inhibitsentry copy.mov Finally, many escape Only catch 6% of the lobsters than enter a trap. Subsequent studies, with other species, also confirm these findings. /Users/localadmin/Desktop/Senso ry Talk Norway 2011/Movies/ltvlargenterchasesmall copy 2.mov In fact, it is hard to imagine the chaos, given the average catch of 1 keeper/trap Therefore, catch in standard traps is not a good indicator of the number of lobsters on the bottom Good news: probably one reason fishery is still exists Bad news: we can’t track the fishery with catch data Maybe Ventless Traps are the Answer /Users/localadmin/Desktop/Norwa y/Norway Talk and Poster Stuff/Movies and images/ltv ventless fast.mov /Users/localadmin/Desktop/Norway/Norway Talk and Poster Stuff/Movies and images/LTV fast standard.mov The relationship between catch in ventless traps and abundance is pretty good compared to standard traps. But also deteriorates a bit at the highest densities. Why? They also saturate*, like standard traps Note: Y-axis different. Standard Traps “Saturate” very quickly, compared to ventless traps. * Catch as many lobsters as possible for a given soak Why do traps saturate? Data from watching videos of standard traps*: “Saturate” very quickly because the rate of entry = rate of exit. * Kyle Jenks and Abigail Clark In contrast….. Day 1: No saturation. Continuous entry, with few escapes. But in day two things change, for reasons we do not understand. Thanks to all, and to all a good night! win jason knot 2 diving crew three amigos tom getting ready to dive Questions? More Info: www.win.unh.edu or www.lobsters.unh.edu