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Massachusetts · Dover County · River

Charles River (between the Medway Dam in Franklin and Medway and the South…

Is the fish you caught here safe to eat? Below is every consumption advisory on file for Charles River (between the Medway Dam in Franklin and Medway and the South…, by species and size, in plain English — plus what's legal to keep.

1 species with advisories · contaminants: Chlordane, DDT, Mercury

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 Charles River (between the Medway Dam in Franklin and Medway and the South… below.

Strictest statewide rule: All Other Species — For women who may become pregnant, pregnant or breastfeeding women, and children under 15: do not eat due to elevated Mercury.

See all Massachusetts statewide guidance →

What's safe to eat from Charles River (between the Medway Dam in Franklin and Medway and the South…

All Other Species

Chlordane DDT Mercury

SizeWhoGuidance
All sizes General population Limit to two meals per month due to elevated Chlordane, DDT and Mercury.
Women who may become pregnant & children under 15 For women who may become pregnant, pregnant or breastfeeding women, and children under 15: do not eat due to elevated Chlordane, DDT and Mercury.

Source: official advisory· updated 2026-07-02

How to prepare fish from Charles River (between the Medway Dam in Franklin and Medway and the South…

Some contaminants build up in fat and skin, so cleaning and cooking can lower your exposure. Others — mercury and PFAS — are in the muscle itself and trimming does nothing.

Chlordane

  • Skin the fish — most of the contaminant sits in the fat just under the skin.
  • Trim the fatty areas away: the belly flap, the top of the back, and the dark lateral line down each side.
  • Cook on a rack — grill, broil, or bake — so the fat drips off the fillet.
  • Throw the drippings out; don't use them for soup, sauce, or chowder.
  • Choose smaller, younger fish — they've had less time to build it up.

DDT

  • Skin the fish — most of the contaminant sits in the fat just under the skin.
  • Trim the fatty areas away: the belly flap, the top of the back, and the dark lateral line down each side.
  • Cook on a rack — grill, broil, or bake — so the fat drips off the fillet.
  • Throw the drippings out; don't use them for soup, sauce, or chowder.
  • Choose smaller, younger fish — they've had less time to build it up.

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

  • Canoe / kayak launch canoe launch 2.5 mi Directions
  • Lake Winthrop Shorefishing Area boat ramp 3.4 mi Directions
  • Boat ramp boat ramp 3.6 mi Directions

Access points from OpenStreetMap contributors.

About this water

State
Massachusetts
County
Dover
Type
River
Full name
Charles River (between the Medway Dam in Franklin and Medway and the South Natick Dam in Natick)
Location
42.1384, -71.4245
Advisory source
Massachusetts DPH — Freshwater Fish Consumption Advisory List