NEFSC Abundance of the Gulf of Maine and Bay of Fundy Harbor Porpoise Based on Aerial Surveys 1999

NOAA Northeast Fisheries Science Center (NEFSC)

Dataset credit

NOAA Northeast Fisheries Science Center (NEFSC)


Primary contact Beth Josephson NOAA Fisheries
Secondary contact Debi Palka NOAA Northeast Fisheries Science Center
Data entry Ei Fujioka Duke University


Josephson, B. and D. Palka. 2018. NEFSC Abundance of the Gulf of Maine and Bay of Fundy Harbor Porpoise Based on Aerial Surveys 1999. Data downloaded from OBIS-SEAMAP ( on yyyy-mm-dd.


The 1994 Amendments to the Marine Mammal Protection Act (MMPA) mandates periodic assessments of all cetacean stocks in US waters. To fulfill this mandate for the Gulf of Maine/Bay of Fundy harbor porpoise stock, the National Marine Fisheries Service (NMFS) has conducted line transect abundance surveys during the summers of 1991, 1992, 1995, and 1999 and provided annual estimates of harbor porpoise by-catch from US sink gillnet fisheries. As well, incidental takes of bycatch in the Canadian sink gillnet and herring weir fisheries have also been documented.

Abundance estimates increased from 37,000 in 1991 to 74,000 in 1995 (Table 1A; Smith et al. 1993, Palka 1995a, Palka 1996a). By-catch in the US Northeast sink gillnet fishery decreased from 2,900 animals in 1990 to 332 in 1998 (Table 1B; Bravington and Bisack 1996; Bisack 1997; Rossman and
Merrick 1999). Harbor porpoise by-catch in the US mid-Atlantic coastal gillnet fisheries varied from a low of 103 in 1995 to a high of 572 in 1997 (Rossman and Merrick 1999). By-catch in the Canadian sink gillnet fishery decreased from 424 in 1993 to 10 in 1998 (Trippel et al. 1996, 1999).
By-catch in the Canadian herring weir fishery decreased from 33 observed takes in 1993 to 2 in 1998 (Waring et al. 1999). Study area, field procedures and analysis methods used in the 1999 abundance survey were similar to those used during previous surveys (Smith et al. 1993, Palka 1995a, Palka
1996a). This paper presents a description of the field procedures, analysis methods and results from the 1999 survey and compares the abundance estimates from 1991 to 1999.



Supplemental information

Perpendicular distance to the animal is not publicly available.




This section explains attributes included in the original dataset. OBIS-SEAMAP restricts the attributes available to the public to date/time, lat/lon and species names/counts only. Should you need other attributes described here, you are encouraged to contact the data provider.

Attributes described below represent those in the original dataset provided by the provider.
All attributes are included in the downloadable file (CSV or ESRI File Geodatabase) for "Complete Set of Dataset".

Attributes in dataset

Attribute (table column)Description
oidUnique ID number (generated by OBIS-SEAMAP)
cruisenumCruise Number
speciesSpecies code
sp_tsnTaxonomic Serial Number added by OBIS-SEAMAP
groupsizeGroup size
transectTransect No.
beaufortBeaufort sea state
psdParpendicular distance
qualityGeneral sighting quality as seen by the port and starboard observers, where the first number is the port observer and the second number is the starboard observer
opareaOparea (always Northeast)
cloudPercent cloud cover, usually rounded to 10 degrees
glare_magGlare code
platformPlatform (always Aerial)
species_codeSpecies code
offonFlag (1/0) to indicate on effort
dateDate of the sighting
timeTime of the sighing at local time zone
sightlatLatitude at decimal degrees
sightlonLongitude at decimal degrees
geomGeometry field added by OBIS-SEAMAP
Marine mammals143
Sea turtles36
Rays and sharks11
Other species13
Non spatial0
Non species0
Date, Begin1999-08-10
Date, End1999-08-29
Temporal prec.111111
Latitude40.87 - 45.16
Longitude-70.41 - -61.01
Coord. prec.3 decimal digits
Data typeAnimal sighting
EffortYES (ID: 1896)
Traveled (km)5,688
Effort hours28
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