Massachusetts · Tyngsborough County · River

Merrimack River (from the MA/NH state line to Broadway Dam in Lawrence)

Is the fish you caught here safe to eat? Below is every consumption advisory on file for Merrimack River (from the MA/NH state line to Broadway Dam in Lawrence), by species and size, in plain English — plus what's legal to keep.

3 species with advisories · contaminants: Mercury, PFAS

Massachusetts also has statewide guidance

Massachusetts publishes rules that apply to rivers across the state — 1 recommendation covering 1 species — in addition to anything listed for Merrimack River (from the MA/NH state line to Broadway Dam in Lawrence) below.

Strictest statewide rule: All Other Species — For children under 12 and people who are nursing, pregnant, or may become pregnant: do not eat due to elevated Mercury.

See all Massachusetts statewide guidance →

What's safe to eat from Merrimack River (from the MA/NH state line to Broadway Dam in Lawrence)

Largemouth Bass

Mercury PFAS

SizeWhoGuidance
All sizes Children under 12 and people who are nursing, pregnant, or may become pregnant For children under 12 and people who are nursing, pregnant, or may become pregnant: do not eat due to elevated Mercury and PFAS.

Source: official advisory· updated 2026-11-06

White Sucker

Mercury PFAS

SizeWhoGuidance
All sizes Children under 12 and people who are nursing, pregnant, or may become pregnant For children under 12 and people who are nursing, pregnant, or may become pregnant: do not eat due to elevated Mercury and PFAS.

Source: official advisory· updated 2026-11-06

All Other Species

Mercury PFAS

SizeWhoGuidance
All sizes All other people Limit to 6 meals per year due to elevated Mercury and PFAS.
Children under 12 and people who are nursing, pregnant, or may become pregnant For children under 12 and people who are nursing, pregnant, or may become pregnant: limit to 2 meals per year due to elevated Mercury and PFAS.

Source: official advisory· updated 2026-11-06

Is it legal to keep?

These are Massachusetts's statewide limits — a water-specific rule may override them. Always verify the current regulations before keeping a fish.

SpeciesSizeDaily limitOpen seasonKeep season
Largemouth Bass 12" min 5 Year-round Same as open
Smallmouth Bass 12" min 5 Year-round Same as open
Northern Pike 28" min 2 Year-round Same as open
Chain Pickerel 15" min 5 Year-round Same as open
Walleye 14" min 5 Year-round Same as open
Inland Trout — 3 Year-round Same as open

Official rules: Massachusetts — Massachusetts DFW

Getting on the water

Access points from OpenStreetMap contributors.

About this water

State
Massachusetts
County
Tyngsborough
Type
River
Location
42.6474, -71.3344
Advisory source
Massachusetts DPH — Freshwater Fish Consumption Advisory List