Decrease in size at maturity of female American lobsters Homarus americanus (H. Milne Edwards, 1837) (Decapoda: Astacidea: Nephropidae) over a 50-year period in Maine, USA

The size at which female American lobsters Homarus americanus (H. Milne Edwards, 1837) reach maturity was determined for females collected from inshore (< 3 nautical miles, or 5.5 km) Boothbay Harbor (BBH), Maine, USA in 2018. A total of 272 females were collected during a three-week period in the spring and each female was assigned a maturity status (immature or mature) based on ovarian staging. These determinations were then compared to two similar female-maturity studies undertaken in BBH by the Maine Department of Marine Resources over the last 50 years. The comparison revealed that the length at which 50% of females reach maturity has decreased by 5 mm over the last 25 years and a significant difference between maturity ogives generated over time in BBH. Cement-gland stage was also recorded for all females and further analysis revealed no significant difference between maturity ogives generated using ovarian and cement-gland staging. Results indicate that cement-gland staging is an effective maturity assessment method in female lobsters from this region. Because there is a well-documented relationship between temperature and size at maturity in crustaceans, we also examined changes in sea-surface temperature during this period in BBH. We found that the region has warmed significantly over this period of time with extreme high temperatures occurring more frequently during the last 25 years. Our results can be used to update key parameters in the stock-assessment model related to growth and egg production in the Gulf of Maine/George’s Bank stock. These findings can also be used to inform future management decisions related to the carapace length of harvested lobsters and the preservation of mature females.

[1]  M. Comeau,et al.  Functional anatomy of the female reproductive system of the American lobster (Homarus americanus) , 2018, Journal of morphology.

[2]  B. Sainte‐Marie,et al.  Spatio-temporal patterns and reproductive costs of abnormal clutches of female American lobster, Homarus americanus, in eastern Canada , 2018, ICES Journal of Marine Science.

[3]  B. Sainte‐Marie,et al.  Female American lobster (Homarus americanus) size-at-maturity declined in Canada during the 20th and early 21st centuries , 2018, Canadian Journal of Fisheries and Aquatic Sciences.

[4]  J. Hanson,et al.  American lobster: persistence in the face of high, size-selective, fishing mortality — a perspective from the southern Gulf of St. Lawrence , 2018, Canadian Journal of Fisheries and Aquatic Sciences.

[5]  Katherine E. Mills,et al.  Seasonal trends and phenology shifts in sea surface temperature on the North American northeastern continental shelf , 2017 .

[6]  Tracy L. Pugh,et al.  Multi-scale quantification of the effects of temperature on size at maturity in the American lobster (Homarus americanus) , 2017 .

[7]  Andrew C. Thomas,et al.  Slow adaptation in the face of rapid warming leads to collapse of the Gulf of Maine cod fishery , 2015, Science.

[8]  Tracy L. Pugh,et al.  A noninvasive method for in situ determination of mating success in female American lobsters (Homarus americanus). , 2014, Journal of Visualized Experiments.

[9]  Tracy L. Pugh,et al.  At-sea determination of female American lobster (Homarus americanus) mating activity: Patterns vs. expectations , 2013 .

[10]  L. WatsonFiona,et al.  Spatial and temporal variation in size at maturity for female American lobster in Nova Scotia , 2013 .

[11]  Kevin W Eliceiri,et al.  NIH Image to ImageJ: 25 years of image analysis , 2012, Nature Methods.

[12]  D. Aiken,et al.  Controlling Growth And Reproduction In The American Lobster , 2009 .

[13]  D. Aiken,et al.  Impact of Invalid Biological Assumptions and Misapplication of Maturity Criteria on Size-at-Maturity Estimates for American Lobster , 2005 .

[14]  P. Ouellet,et al.  Changes in yolk total proteins and lipid components and embryonic growth rates during lobster (Homarus americanus) egg development under a simulated seasonal temperature cycle , 2004 .

[15]  S. Saila,et al.  Changes in female lobster (Homarus americanus) size at maturity and implications for the lobster resource in Long Island Sound, Connecticut , 2001 .

[16]  D. Aiken,et al.  Environmental intervention in the reproductive process of the American lobster, Homarus americanus , 1992 .

[17]  D. Aiken,et al.  Multiple Fertilization and Consecutive Spawning in Large American Lobsters, Homarus americanus , 1986 .

[18]  D. Aiken,et al.  CEMENT GLAND DEVELOPMENT, OVARY MATURATION, AND REPRODUCTIVE CYCLES IN THE AMERICAN LOBSTER HOMARUS AMERICANUS , 1982 .

[19]  G. P. Ennis.  Size–Maturity Relationships and Related Observations in Newfoundland Populations of the Lobster (Homarus americanus) , 1980 .

[20]  D. Aiken.  Proecdysis, Setal Development, and Molt Prediction in the American Lobster (Homarus americanus) , 1973 .

[21]  G. Matthiessen,et al.  OBSERVATIONS ON THE BIOLOGY OF THE AMERICAN LOBSTER, HOMARUS AMERICANUS , 1962 .

[22]  Tracy L. Pugh,et al.  Evidence of mating by sexually immature female American lobsters Homarus americanus (H. Milne Edwards, 1837) (Decapoda: Nephropidae) , 2017 .

[23]  Andrew C. Thomas,et al.  Fisheries Management in a Changing Climate Lessons from the 2012 Ocean Heat Wave in the Northwest Atlantic , 2013 .

[24]  P. Ouellet,et al.  AN INVESTIGATION OF THE SOURCES OF VARIABILITY IN AMERICAN LOBSTER (HOMARUS AMERICANUS) EGGS AND LARVAE: FEMALE SIZE AND REPRODUCTIVE STATUS, AND INTERANNUAL AND INTERPOPULATION COMPARISONS , 2004 .

[25]  M. Comeau,et al.  MATURITY AND REPRODUCTIVE CYCLE OF THE FEMALE AMERICAN LOBSTER, HOMARUS AMERICANUS, IN THE SOUTHERN GULF OF ST. LAWRENCE, CANADA , 2002 .

[26]  D. Kleijn,et al.  Chapter 10 – Control of Growth and Reproduction , 1995 .

[27]  Jay S. Krouse.  MATURITY, SEX RATIO, AND SIZE COMPOSITION OF THE NATURAL POPULATION OF AMERICAN LOBSTER, HOMARUS A MERICANUS, ALONG THE MAINE COAST' , 1973 .