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

NOAA Northeast Fisheries Science Center (NEFSC)

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.

N/A

Perpendicular distance to the animal is not publicly available.

Overview

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
oid	Unique ID number (generated by OBIS-SEAMAP)
cruisenum	Cruise Number
species	Species code
sp_tsn	Taxonomic Serial Number added by OBIS-SEAMAP
groupsize	Group size
transect	Transect No.
leg	Leg
beaufort	Beaufort sea state
psd	Parpendicular distance
quality	General 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
oparea	Oparea (always Northeast)
cloud	Percent cloud cover, usually rounded to 10 degrees
glare_mag	Glare code
platform	Platform (always Aerial)
species_code	Species code
offon	Flag (1/0) to indicate on effort
date	Date of the sighting
time	Time of the sighing at local time zone
card	Card
sightlat	Latitude at decimal degrees
sightlon	Longitude at decimal degrees
depth	Depth
geom	Geometry field added by OBIS-SEAMAP